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TI-2025-41791 Aliases CVE-2025-68214GHSA-q35m-cwfx-j6jx

timers: Fix NULL function pointer race in timer_shutdown_sync()

Priority LOW 21CWE-362Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
High
Impact type
—
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 10 fixed, 1 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat.

Summary

In the Linux kernel, the following vulnerability has been resolved: timers: Fix NULL function pointer race in timer_shutdown_sync() There is a race condition between timer_shutdown_sync() and timer expiration that can lead to hitting a WARN_ON in expire_timers(). The issue occurs when timer_shutdown_sync() clears the timer function to NULL while the timer is still running on another CPU. The race scenario looks like this: CPU0 CPU1 <SOFTIRQ> lock_timer_base() expire_timers() base->running_timer = timer; unlock_timer_base() [call_timer_fn enter] mod_timer() ... timer_shutdown_sync() lock_timer_base() // For now, will not detach the timer but only clear its function to NULL if (base->running_timer != timer) ret = detach_if_pending(timer, base, true); if (shutdown) timer->function = NULL; unlock_timer_base() [call_timer_fn exit] lock_timer_base() base->running_timer = NULL; unlock_timer_base() ... // Now timer is pending while its function set to NULL. // next timer trigger <SOFTIRQ> expire_timers() WARN_ON_ONCE(!fn) // hit ... lock_timer_base() // Now timer will detach if (base->running_timer != timer) ret = detach_if_pending(timer, base, true); if (shutdown) timer->function = NULL; unlock_timer_base() The problem is that timer_shutdown_sync() clears the timer function regardless of whether the timer is currently running. This can leave a pending timer with a NULL function pointer, which triggers the WARN_ON_ONCE(!fn) check in expire_timers(). Fix this by only clearing the timer function when actually detaching the timer. If the timer is running, leave the function pointer intact, which is safe because the timer will be properly detached when it finishes running.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00128 2nd percentileScored 2026-11-07
Fix Partial Linux (Linux): 6.1.159, 6.6.118, 6.12.60 +2Red Hat: 2 advisoriesRed Hat: 10 fixed, 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux6.1.158 to before 6.1.1596.1.159Patch availableCNA
LinuxLinux6.2 and later6.1.159, 6.6.118, 6.12.60, 6.17.10, 6.18Patch availableCNA
  • Linux VendorLinux Affected 6.1.158 to before 6.1.159 Fixed in 6.1.159 Patch available CNA
  • Linux VendorLinux Affected 6.2 and later Fixed in 6.1.159, 6.6.118, 6.12.60, 6.17.10, 6.18 Patch available CNA

CPE configurations NVD · 8

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*6.2 to before 6.6.118; 6.7 to before 6.12.60; 6.13 to before 6.17.10VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.1.158:*:*:*:*:*:*:*6.1.158VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.18:rc1:*:*:*:*:*:*6.18 rc1VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.18:rc2:*:*:*:*:*:*6.18 rc2VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.18:rc3:*:*:*:*:*:*6.18 rc3VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.18:rc4:*:*:*:*:*:*6.18 rc4VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.18:rc5:*:*:*:*:*:*6.18 rc5VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.18:rc6:*:*:*:*:*:*6.18 rc6VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 6.2 to before 6.6.118; 6.7 to before 6.12.60; 6.13 to before 6.17.10 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.1.158:*:*:*:*:*:*:* Versions 6.1.158 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.18:rc1:*:*:*:*:*:* Versions 6.18 rc1 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.18:rc2:*:*:*:*:*:* Versions 6.18 rc2 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.18:rc3:*:*:*:*:*:* Versions 6.18 rc3 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.18:rc4:*:*:*:*:*:* Versions 6.18 rc4 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.18:rc5:*:*:*:*:*:* Versions 6.18 rc5 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.18:rc6:*:*:*:*:*:* Versions 6.18 rc6 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 6.1.159
  • Fix · CNA Linux (Linux) Fixed in 6.1.159, 6.6.118, 6.12.60, 6.17.10, 6.18

Red Hat 2 advisories

  • RHSA-2026:49870 Released 2026-08-04 · Red Hat rating Low
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.34.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.34.1.el9_8, kernel-64k-devel-5.14.0-687.34.1.el9_8 +12
    • Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.34.1.el9_8, kernel-64k-5.14.0-687.34.1.el9_8, kernel-64k-core-5.14.0-687.34.1.el9_8 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.34.1.el9_8, libperf-5.14.0-687.34.1.el9_8
    • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.34.1.el9_8, kernel-rt-64k-5.14.0-687.34.1.el9_8, kernel-rt-64k-core-5.14.0-687.34.1.el9_8 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.34.1.el9_8, kernel-rt-core-5.14.0-687.34.1.el9_8, kernel-rt-debug-5.14.0-687.34.1.el9_8 +9
  • RHSA-2026:49871 Released 2026-08-04 · Red Hat rating Moderate
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.43.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.43.1.el10_2, kernel-64k-devel-6.12.0-211.43.1.el10_2 +12
    • Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.43.1.el10_2, kernel-64k-6.12.0-211.43.1.el10_2, kernel-64k-core-6.12.0-211.43.1.el10_2 +29
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.43.1.el10_2, libperf-6.12.0-211.43.1.el10_2
    • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.43.1.el10_2, kernel-rt-64k-6.12.0-211.43.1.el10_2, kernel-rt-64k-core-6.12.0-211.43.1.el10_2 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.43.1.el10_2, kernel-rt-core-6.12.0-211.43.1.el10_2, kernel-rt-debug-6.12.0-211.43.1.el10_2 +9

Vendor assessments

Red Hat

Red Hat rating: Low. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 8AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:49871
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:49870
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2026:49871
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2026:49870
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:49871
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:49870
Red Hat Enterprise Linux Real Time (v. 10)Fixed RHSA-2026:49871
Red Hat Enterprise Linux Real Time (v. 9)Fixed RHSA-2026:49870
Red Hat Enterprise Linux Real Time for NFV (v. 10)Fixed RHSA-2026:49871
Red Hat Enterprise Linux Real Time for NFV (v. 9)Fixed RHSA-2026:49870
Not affected: 3 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-68214
  2. 2026-10-03 Alias added: GHSA-q35m-cwfx-j6jx
  3. 2026-10-29 Affected versions changed · Red Hat
  4. 2026-11-05 CISA SSVC decision points changed

References

Patch 6

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
  • TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
See all 15278 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences