SB2026092973 - Ubuntu update for linux-aws-5.15

Description

This security bulletin contains information about 31 vulnerabilities.

1) Out-of-bounds read (CVE-ID: CVE-2026-63992)

CWE-ID: CWE-125 - Out-of-bounds read

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to an out-of-bounds read in iptunnel_pmtud_check_icmp() when processing ICMP packets without a valid transport header. A remote attacker can send a specially crafted packet to cause a denial of service.

The issue occurs because the function may be called while the skb transport header is not set.

2) Out-of-bounds read (CVE-ID: CVE-2026-53186)

CWE-ID: CWE-125 - Out-of-bounds read

CVSSv4: 6.9 [CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote user to cause a denial of service.

The vulnerability exists due to an out-of-bounds read in srp_process_rsp() when processing a crafted SRP_RSP response from an SRP target. A remote user can send a specially crafted SRP_RSP with SRP_RSP_FLAG_SNSVALID set and a large resp_data_len value to cause a denial of service.

Exploitation requires that the initiator is logged into a malicious or compromised SRP target on the InfiniBand or RoCE fabric.

3) Out-of-bounds write (CVE-ID: CVE-2026-53216)

CWE-ID: CWE-787 - Out-of-bounds write

CVSSv4: 6.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to corrupt memory or cause a denial of service.

The vulnerability exists due to an out-of-bounds write in the mvpp2 XDP receive path when processing packets with XDP tail adjustment on short RX buffers. A local user can trigger bpf_xdp_adjust_tail() on a packet to corrupt memory or cause a denial of service.

The issue occurs because the XDP frame size is initialized larger than the actual backing buffer size for short BM pool buffers.

4) Improper input validation (CVE-ID: CVE-2026-53221)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause traffic to be associated with the wrong tunnel.

The vulnerability exists due to improper input validation in vti6_tnl_lookup() when matching IPv6 VTI tunnels during fallback wildcard tunnel searches. A remote attacker can send network traffic that triggers a hash collision and incorrect tunnel selection to cause traffic to be associated with the wrong tunnel.

The issue occurs because candidate tunnels in the fallback search were not verified to actually use wildcard local or remote addresses.

5) Race condition (CVE-ID: CVE-2026-53354)

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to improper synchronization in broadcast TLBI completion handling in the arm64 CPU errata logic when performing broadcast TLB invalidation on affected Arm CPUs. A local user can trigger memory management activity to cause a denial of service.

The issue affects completion of memory accesses translated by an invalidated TLB entry, while TLB invalidation itself still occurs correctly.

6) Use-after-free (CVE-ID: CVE-2026-53355)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a use-after-free in the rds ib connection teardown path when unwinding a failed queue pair setup. A local user can trigger a setup failure after allocating the send ring to cause a denial of service.

The issue occurs when rds_ib_setup_qp() fails after allocating i_sends but before allocating i_recvs, leaving a stale pointer that may be treated as a live allocation during a later shutdown pass.

7) Improper Initialization (CVE-ID: CVE-2026-53398)

CWE-ID: CWE-665 - Improper Initialization

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper initialization in nfsd4_decode_secinfo_no_name() when processing a truncated XDR stream for the SECINFO_NO_NAME operation. A remote attacker can send a specially crafted request to cause a denial of service.

The issue occurs because stale union contents from a previous operation can leave sin_exp non-NULL, leading the error cleanup path to call exp_put() on an invalid value.

8) Use-after-free (CVE-ID: CVE-2026-63800)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to use-after-free in pnfs_update_layout() when handling the NFS_LAYOUT_RETURN branch. A local user can trigger the vulnerable code path to cause a denial of service.

9) Use-after-free (CVE-ID: CVE-2026-63808)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a use-after-free in exfat_find_dir_entry() when parsing a crafted exFAT filesystem image. A local user can supply a crafted exFAT image to trigger a kernel fault and cause a denial of service.

The issue occurs on the TYPE_EXTEND path after a directory entry buffer is released and then dereferenced.

10) Heap-based buffer overflow (CVE-ID: CVE-2026-63887)

CWE-ID: CWE-122 - Heap-based Buffer Overflow

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to a heap-based buffer overflow in iscsi_encode_text_output() when processing iSCSI login text parameters. A remote attacker can send a specially crafted login request with many minimal key-value pairs to cause a denial of service.

The issue can be triggered by expansion of unknown keys into larger "NotUnderstood" response records during login negotiation.

11) Out-of-bounds read (CVE-ID: CVE-2026-63888)

CWE-ID: CWE-125 - Out-of-bounds read

CVSSv4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote user to cause a denial of service.

The vulnerability exists due to an out-of-bounds read in iscsit_handle_text_cmd() when processing Text PDUs with DataDigest enabled. A remote user can send a specially crafted text request to cause a denial of service.

The issue is triggered when DataDigest is negotiated for the connection.

12) Double free (CVE-ID: CVE-2026-63888)

CWE-ID: CWE-415 - Double Free

CVSSv4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote user to cause a denial of service.

The vulnerability exists due to a double free in iscsit_handle_text_cmd() when handling a Text PDU with a bad DataDigest on connections using ErrorRecoveryLevel greater than 0. A remote user can send a specially crafted text request to cause a denial of service.

On hardened kernels the flaw can trigger a remote kernel BUG(), while on non-hardened kernels it can corrupt the slab freelist. A follow-up Text Request on the same ITT or session teardown can free the same pointer again.

13) Improper input validation (CVE-ID: CVE-2026-63912)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to improper input validation in the ESP out-of-place fast path in net/ipv4/esp4.c and net/ipv6/esp6.c when processing packet data with a combined aligned data length and trailer length exceeding a page. A local user can trigger this condition to cause a denial of service.

The issue affects both IPv4 and IPv6 ESP processing paths.

14) Use-after-free (CVE-ID: CVE-2026-63922)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to a use-after-free risk from stale pointer reuse in ip6_parse_tlv() in net/ipv6/exthdrs.c when parsing IPv6 TLVs containing the HAO option. A remote attacker can send a specially crafted IPv6 packet to cause a denial of service.

The issue occurs when handling a cloned skb where header expansion moves the skb head and invalidates the cached network header pointer.

15) Use of Out-of-range Pointer Offset (CVE-ID: CVE-2026-63924)

CWE-ID: CWE-823 - Use of Out-of-range Pointer Offset

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper pointer handling in the IPv6 extension header parser in net/ipv6/exthdrs.c when processing IPv6 jumbo hop-by-hop options. A remote attacker can send a specially crafted IPv6 packet to cause a denial of service.

16) Integer overflow (CVE-ID: CVE-2026-63984)

CWE-ID: CWE-190 - Integer overflow

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to corrupt memory in a forwarded packet.

The vulnerability exists due to an integer overflow in ipv6_rpl_srh_decompress() and ipv6_rpl_srh_rcv() when processing a crafted IPv6 RPL source routing header. A remote attacker can send a specially crafted packet to corrupt memory in a forwarded packet.

The issue occurs because the computed hdrlen value can truncate to zero for a large segment count, causing the compressed header to overlap the decompressed routing data.

17) Improper locking (CVE-ID: CVE-2025-10263)

CWE-ID: CWE-667 - Improper Locking

CVSSv4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to disclose sensitive information, modify data, or cause a denial of service.

The vulnerability exists due to improper memory synchronization in broadcast TLBI completion in the arm64 TLB invalidation handling when performing broadcast TLB invalidation on affected Arm CPUs. A local user can trigger affected memory access patterns to disclose sensitive information, modify data, or cause a denial of service.

The issue affects completion of memory accesses translated by an invalidated TLB entry, while TLB entries themselves are still invalidated correctly.

18) Use-after-free (CVE-ID: CVE-2026-63993)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to execute arbitrary code.

The vulnerability exists due to a use-after-free in the vxlan_xmit_one function in drivers/net/vxlan/vxlan_core.c when processing packets after skb_tunnel_check_pmtu() updates the skb head. A local user can trigger the vulnerable code path to execute arbitrary code.

19) Use-after-free (CVE-ID: CVE-2026-63994)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a use-after-free in iptunnel_pmtud_build_icmp() and iptunnel_pmtud_build_icmpv6() when processing tunnel PMTU ICMP and ICMPv6 packet generation. A local user can trigger skb_cow() reallocation while stale network header pointers are still used to cause a denial of service.

20) Use-after-free (CVE-ID: CVE-2026-64007)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 8.8 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause memory corruption or a denial of service.

The vulnerability exists due to a use-after-free in synproxy_tstamp_adjust() in the netfilter synproxy implementation when processing crafted TCP packets that trigger header rewriting on a cloned or non-linear skb. A remote attacker can send a specially crafted packet to cause memory corruption or a denial of service.

The issue affects checksum updates after the packet buffer is made writable, which can result in a write to freed slab memory or a transmitted packet with a stale checksum.

21) Time-of-check Time-of-use (TOCTOU) Race Condition (CVE-ID: CVE-2026-64091)

CWE-ID: CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a race condition leading to an out-of-bounds write in batadv_tt_prepare_tvlv_local_data in the batman-adv translation table handling when generating local TT TVLV data for reported VLANs. A local user can trigger concurrent VLAN translation table entry changes to cause a denial of service.

The issue arises from a time-of-check time-of-use condition where the number of non-empty VLANs can increase after buffer sizing but before the buffer is filled.

22) Improper access control (CVE-ID: CVE-2025-10263)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: 7.3 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to escalate privileges.

The vulnerability exists due to improper access control in Stage 2 translation handling when invalidating translation lookaside buffer entries on affected Arm systems. A local user can trigger writes from a malicious guest after write permissions have been revoked to escalate privileges.

Only Xen on Arm in multi-core configurations is affected. The issue does not affect reads.

23) Improper locking (CVE-ID: CVE-2025-10263)

CWE-ID: CWE-667 - Improper Locking

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to improper memory synchronization in broadcast TLB invalidation completion handling in the arm64 CPU errata logic when performing broadcast TLB invalidation on affected Arm CPUs. A local user can trigger memory access patterns that rely on invalidated TLB entries to cause a denial of service.

The issue affects only completion of memory accesses translated by an invalidated TLB entry and does not prevent the actual invalidation of TLB entries.

24) Race condition (CVE-ID: CVE-2025-10263)

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to improper synchronization in broadcast TLB invalidation completion handling in the arm64 TLB invalidation logic when performing memory accesses translated by an invalidated TLB entry after a TLBI;DSB sequence. A local user can trigger affected memory access patterns to cause a denial of service.

The issue affects only the completion of memory accesses translated by an invalidated TLB entry and does not prevent the actual invalidation of TLB entries.

25) Improper locking (CVE-ID: CVE-2025-10263)

CWE-ID: CWE-667 - Improper Locking

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to improper hardware synchronization in arm64 TLB invalidation handling when processing broadcast TLB invalidation sequences on affected Arm CPUs. A local user can trigger memory accesses that rely on an invalidated TLB entry to cause a denial of service.

The issue affects only the completion of memory accesses translated by an invalidated TLB entry and does not affect the actual invalidation of TLB entries.

26) Race condition (CVE-ID: CVE-2025-10263)

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to improper synchronization in broadcast TLB invalidation completion handling in the arm64 CPU errata logic when performing memory accesses translated by an invalidated TLB entry after a TLBI;DSB sequence. A local user can trigger affected memory access patterns to cause a denial of service.

The issue affects certain Arm CPUs on arm64 systems and does not prevent invalidation of TLB entries themselves.

27) Race condition (CVE-ID: CVE-2025-10263)

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSSv4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to improper synchronization in broadcast TLBI completion in the arm64 TLB invalidation handling when performing broadcast TLB invalidation on affected Arm CPUs. A local user can trigger memory access patterns that rely on invalidated TLB entries to cause a denial of service.

The issue affects the completion of memory accesses translated by an invalidated TLB entry, while the TLB invalidation itself still occurs correctly.

28) Improper locking (CVE-ID: CVE-2025-10263)

CWE-ID: CWE-667 - Improper Locking

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to improper hardware synchronization in broadcast TLBI completion on affected arm64 CPUs when performing broadcast TLB invalidation. A local user can trigger memory access activity that relies on an invalidated TLB entry to cause a denial of service.

The issue affects only the completion of memory accesses translated by an invalidated TLB entry; the TLB invalidation itself still occurs correctly.

29) Improper locking (CVE-ID: CVE-2025-10263)

CWE-ID: CWE-667 - Improper Locking

CVSSv4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to disclose sensitive information, modify data, or cause a denial of service.

The vulnerability exists due to improper synchronization in broadcast TLB invalidation handling in the arm64 TLB invalidation logic when processing TLBI and DSB sequences on affected Arm CPUs. A local user can trigger memory accesses involving translations from an invalidated TLB entry to disclose sensitive information, modify data, or cause a denial of service.

The issue affects only the completion of memory accesses translated by an invalidated TLB entry and does not prevent the actual invalidation of TLB entries.

30) Improper locking (CVE-ID: CVE-2025-10263)

CWE-ID: CWE-667 - Improper Locking

CVSSv4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to disclose sensitive information, modify data, or cause a denial of service.

The vulnerability exists due to improper memory access ordering in arm64 TLB invalidation handling when performing broadcast TLB invalidation on affected Arm CPUs. A local user can trigger affected memory access completion conditions to disclose sensitive information, modify data, or cause a denial of service.

The issue affects only memory accesses translated by an invalidated TLB entry; TLB entries themselves are still invalidated correctly.

31) Race condition (CVE-ID: CVE-2025-10263)

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSSv4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to disclose sensitive information, modify data, or cause a denial of service.

The vulnerability exists due to improper memory synchronization in broadcast TLB invalidation completion handling in the arm64 CPU errata handling for affected Arm CPUs when performing broadcast TLB invalidation sequences. A local user can trigger memory accesses relying on an invalidated TLB entry to disclose sensitive information, modify data, or cause a denial of service.

The issue affects only the completion of memory accesses translated by an invalidated TLB entry; the TLB entries themselves are still invalidated correctly.

Remediation

Install update from vendor's website.

References

• https://ubuntu.com/security/notices/USN-8818-3