SB2026061859 - Ubuntu update for linux-azure
Published: June 18, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 18 vulnerabilities.
1) Improper control of a resource through its lifetime (CVE-ID: CVE-2026-31431)
CWE-ID: CWE-664 - Improper control of a resource through its lifetime
CVSSv4: 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/E:A/U:Amber
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to improper memory handling within the authencesn cryptographic template in algif_aead when processing AEAD operations. A local user can trigger the vulnerable code path to execute arbitrary code on the system.
Note, this vulnerability was dubbed "Copy Fail".
2) Resource management error (CVE-ID: CVE-2026-43284)
CWE-ID: CWE-399 - Resource Management Errors
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:A/U:Amber
The vulnerability allows a local user to escalate privileges on the system.
The xfrm-ESP Page-Cache Write vulnerability exists due to improper management of internal resources in esp_input() function in net/ipv4/esp4.c and esp6_input() function in net/ipv6/esp6.c. A local user can execute arbitrary code with root privileges.
Note, this is one of two vulnerabilities reported as Dirty Frag.
3) Resource management error (CVE-ID: CVE-2026-43500)
CWE-ID: CWE-399 - Resource Management Errors
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:A/U:Amber
The vulnerability allows a local user to escalate privileges on the system.
The RxRPC Page-Cache Write vulnerability exists due to improper management of internal resources. A local user can execute arbitrary code with root privileges.
Note, this vulnerability is one of two issues described as Dirty Frag.
4) Improper control of a resource through its lifetime (CVE-ID: CVE-2026-43503)
CWE-ID: CWE-664 - Improper control of a resource through its lifetime
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a local user to modify the page cache of a root-owned read-only file.
The vulnerability exists due to improper state management in frag-transfer helpers in the Linux kernel networking stack when moving fragment descriptors between socket buffers. A local user can trigger packet processing through a duplicated skb path to modify the page cache of a root-owned read-only file.
One demonstrated path involves ESP input after a packet is duplicated through an nft 'dup to' rule or another nf_dup_ipv4() / xt_TEE caller.
5) Improper control of a resource through its lifetime (CVE-ID: CVE-2026-46300)
CWE-ID: CWE-664 - Improper control of a resource through its lifetime
CVSSv4: 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/E:U/U:Clear
The vulnerability allows a local user to cause memory corruption.
The vulnerability exists due to improper state management in skb_try_coalesce() when transferring paged fragments during TCP receive coalescing. A local user can trigger packet processing that moves shared fragments into an unmarked skb to cause memory corruption.
The issue can lead ESP input to incorrectly treat an uncloned nonlinear skb as not having shared fragments and perform in-place decryption over externally owned or page-cache-backed fragments.
6) Improper access control (CVE-ID: CVE-2026-46333)
CWE-ID: CWE-284 - Improper Access Control
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:A/U:Clear
The vulnerability allows a local privileged user to disclose sensitive information.
The vulnerability exists due to improper access control in ptrace_may_access() when checking dumpability for tasks without an associated mm pointer. A local privileged user can inspect kernel thread details to disclose sensitive information.
The issue affects cases involving threads that no longer have a VM or never had one, such as kernel threads.
7) Race condition (CVE-ID: CVE-2026-46028)
CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CVSSv4: 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/E:U/U:Clear
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to improper state management in the algif_aead AF_ALG AEAD request handling when processing asynchronous AEAD AIO requests. A local user can trigger concurrent socket activity to cause a denial of service.
The issue arises because in-flight operations depend on a mutable socket-wide IV buffer that can be changed before the original request completes.
8) Double free (CVE-ID: CVE-2026-43494)
CWE-ID: CWE-415 - Double Free
CVSSv4: 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/E:U/U:Clear
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to a double free in rds_message_zcopy_from_user() and rds_message_purge() when handling a zerocopy page pin failure during sendmsg processing. A local user can trigger a page pin failure and subsequent cleanup to cause a denial of service.
9) Out-of-bounds write (CVE-ID: CVE-2026-43078)
CWE-ID: CWE-787 - Out-of-bounds write
CVSSv4: 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/E:U/U:Clear
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to an out-of-bounds write in af_alg_pull_tsgl when reassigning pages. A local user can trigger page reassignment that reassigns one more page than necessary to cause a denial of service.
10) Improper input validation (CVE-ID: CVE-2026-43077)
CWE-ID: CWE-20 - Improper input validation
CVSSv4: 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/E:U/U:Clear
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to improper input validation in algif_aead when processing decryption requests. A local user can provide a crafted receive buffer size to cause a denial of service.
11) Always-Incorrect Control Flow Implementation (CVE-ID: CVE-2026-43033)
CWE-ID: CWE-670 - Always-Incorrect Control Flow Implementation
CVSSv4: 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/E:U/U:Clear
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to improper handling of high-order sequence bits in authencesn when decrypting data out of place. A local user can trigger out-of-place decryption with a specially crafted data layout to cause a denial of service.
12) Use-after-free (CVE-ID: CVE-2026-31533)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 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/E:U/U:Clear
The vulnerability allows a local user to cause a use-after-free.
The vulnerability exists due to use-after-free in tls_do_encryption() when handling an -EBUSY error path during asynchronous encryption processing. A local user can trigger asynchronous encryption and a subsequent sendmsg to cause a use-after-free.
The issue occurs because a pending cryptd callback may access a freed tls_rec after cleanup state is corrupted by double handling of encrypt_pending and scatterlist restoration.
13) Use-after-free (CVE-ID: CVE-2026-31504)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 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/E:U/U:Clear
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to a use-after-free in packet_release() and fanout group handling when processing a concurrent NETDEV_UP event during socket release. A local user can trigger a race condition to cause a denial of service.
The issue affects fanout sockets during a race that can leave a dangling pointer in the fanout array.
14) Use-after-free (CVE-ID: CVE-2026-31419)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 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/E:U/U:Clear
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to a use-after-free in bond_xmit_broadcast() when transmitting broadcast packets during concurrent slave enslave or release operations. A local user can trigger concurrent network interface state changes and packet transmission to cause a denial of service.
The issue arises because the determination of the last slave can change during RCU-protected iteration, leading to double consumption and double free of the original skb.
15) Use After Free (CVE-ID: CVE-2026-23351)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 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/E:U/U:Clear
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to a use-after-free in the netfilter nft_set_pipapo component when handling a large number of expired elements during commit-time garbage collection. A local user can trigger prolonged non-preemptible execution to cause a denial of service.
Exploitation requires triggering garbage collection under a large number of expired elements, leading to soft lockup warnings and RCU stall reports.
16) Exposure of resource to wrong sphere (CVE-ID: CVE-2026-23274)
CWE-ID: CWE-668 - Exposure of resource to wrong sphere
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to improper input validation in the netfilter xt_IDLETIMER module when processing timer rules with reused labels. A local user can insert a revision 0 IDLETIMER rule with a label that was previously used by a revision 1 rule with XT_IDLETIMER_ALARM, leading to modification of an uninitialized timer_list object, which can trigger debugobjects warnings and potentially cause a kernel panic when panic_on_warn=1 is enabled.
Exploitation requires the ability to load netfilter rules. The impact is limited to denial of service via system crash under specific kernel configurations.
17) Improper locking (CVE-ID: CVE-2024-50060)
CWE-ID: CWE-667 - Improper Locking
CVSSv4: 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/E:U/U:Clear
The vulnerability allows a local user to perform a denial of service (DoS) attack.
The vulnerability exists due to improper locking within the __io_cqring_overflow_flush() function in io_uring/io_uring.c. A local user can perform a denial of service (DoS) attack.
18) Use-after-free (CVE-ID: CVE-2024-35862)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 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/E:U/U:Clear
The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a use-after-free error within the smb2_is_network_name_deleted() function in fs/smb/client/smb2ops.c. A remote non-authenticated attacker can perform a denial of service (DoS) attack.
Remediation
Install update from vendor's website.