SB20261021134 - Red Hat Enterprise Linux 8 update for kernel-rt
Published: October 21, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 7 vulnerabilities.
1) Out-of-bounds read (CVE-ID: CVE-2026-64114)
CWE-ID: CWE-125 - Out-of-bounds read
CVSSv4: 5.6 [CVSS:4.0/AV:L/AC:L/AT:P/PR:H/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 an out-of-bounds access in the raw_send_hdrinc IPv4 packet handling in the Linux kernel when processing a malformed IP_HDRINCL packet with an IPv4 header length value less than 5. A local user can send a specially crafted packet through a raw socket to cause a denial of service.
Exploitation requires CAP_NET_RAW. Triggering the reproduced crash path also requires a matching xfrm AH policy on the outgoing route, and loopback does not reach the affected path.
2) Use-after-free (CVE-ID: CVE-2026-64266)
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 fuse_ref_folio() in the FUSE subsystem when handling a subsequent copy chain after unlocking the request. A local user can trigger request abort and asynchronous end callback timing to cause a denial of service.
3) Use-after-free (CVE-ID: CVE-2026-64572)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 5.6 [CVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a local privileged user to cause a denial of service.
The vulnerability exists due to a use-after-free in fib_table_lookup() and the IPv4 FIB alias list handling in fib_trie.c when processing concurrent route insertion failure and lookup operations. A local privileged user can trigger a route insertion error path and perform a concurrent lookup to cause a denial of service.
Exploitation requires CAP_NET_ADMIN and a registered FIB notifier that can reject a route, such as when an IPv4 FIB resource is exhausted on a netdevsim device.
4) Use-after-free (CVE-ID: CVE-2026-68202)
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 ALSA sequencer queue timer handling in snd_seq_timer_delete() and related queue destruction logic when accessing /dev/snd/seq and re-opening a queue timer during queue teardown. A local user can issue crafted sequencer operations to leave a timer instance live and trigger a dereference of freed queue memory to cause a denial of service.
No queue ownership is required.
5) Out-of-bounds write (CVE-ID: CVE-2026-80536)
CWE-ID: CWE-787 - Out-of-bounds write
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 remote attacker to execute arbitrary code.
The vulnerability exists due to an out-of-bounds write in xlog_recover_do_reg_buffer() when processing a crafted XFS filesystem image during mount-time log recovery. A remote attacker can mount a specially crafted filesystem image to execute arbitrary code.
The issue is reachable during mount-time recovery on production kernels where the bounds check was enforced only by an ASSERT().
6) Always-Incorrect Control Flow Implementation (CVE-ID: CVE-2026-80590)
CWE-ID: CWE-670 - Always-Incorrect Control Flow Implementation
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 handling of gso metadata in inet fragment reassembly when processing crafted IP fragments with attached GSO state. A local user can write specially crafted packets to a tap device to cause a denial of service.
The issue can be triggered by an unprivileged user in its own user namespace, and it may also be reachable in environments where virtio_net_hdr metadata is forwarded to a tap device or where CAP_NET_RAW is available in a network namespace.
7) Use-after-free (CVE-ID: CVE-2026-89777)
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 compromise system confidentiality, integrity, and availability.
The vulnerability exists due to use-after-free caused by a dangling pointer in vfio pci MSI permission-table handling when MSI permission-table initialization fails. A local user can cause MSI permission-table initialization to fail and subsequently access MSI configuration to compromise system confidentiality, integrity, and availability.
The per-device structure persists across open and close cycles.
Remediation
Install update from vendor's website.