CVE-2026-46173
exit: prevent preemption of oopsing TASK_DEAD task
In the Linux kernel, the following vulnerability has been resolved: exit: prevent preemption of oopsing TASK_DEAD task When an already-exiting task oopses, make_task_dead() currently calls do_task_dead() with preemption enabled. That is forbidden: do_task_dead() calls __schedule(), which has a comment saying "WARNING: must be called with preemption disabled!". If an oopsing task is preempted in do_task_dead(), between becoming TASK_DEAD and entering the scheduler explicitly, bad things happen: finish_task_switch() assumes that once the scheduler has switched away from a TASK_DEAD task, the task can never run again and its stack is no longer needed; but that assumption apparently doesn't hold if the dead task was preempted (the SM_PREEMPT case). This means that the scheduler ends up repeatedly dropping references on the dead task's stack, which can lead to use-after-free or double-free of the entire task stack; in other words, two tasks can end up running on the same stack, resulting in various kinds of memory corruption. (This does not just affect "recursively oopsing" tasks; it is enough to oops once during task exit, for example in a file_operations::release handler)
Fixes and workarounds
No remediation reported in collected sources.
Missing remediation information is not evidence that no patch exists.
Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| Linux Linux |
≥ 7f80a2fd7db9a55894fd841915236aca611291b5; < 3d6fb8a7690c23e3213c4b008f64d89a44b98737 (affected, git) ≥ 7f80a2fd7db9a55894fd841915236aca611291b5; < 640b4c00fb0e2920327435f6176cbefc3c546165 (affected, git) ≥ 7f80a2fd7db9a55894fd841915236aca611291b5; < 7b2800ba5f5f77a8ee7f4cbadb19cf1264597a34 (affected, git) ≥ 7f80a2fd7db9a55894fd841915236aca611291b5; < 6f49f94f3b11fe8bff1bf2a054143789e76aaf17 (affected, git) ≥ 7f80a2fd7db9a55894fd841915236aca611291b5; < 9756b3db5db6c2f5eccb32dddbd88eb4c54f575e (affected, git) ≥ 7f80a2fd7db9a55894fd841915236aca611291b5; < c1fa0bb633e4a6b11e83ffc57fa5abe8ebb87891 (affected, git) Other versions: unaffected |
CNA: Linux |
| Linux Linux |
5.17 (affected) ≥ 0; < 5.17 (unaffected, semver) ≥ 6.1.175; ≤ 6.1.* (unaffected, semver) ≥ 6.6.140; ≤ 6.6.* (unaffected, semver) ≥ 6.12.88; ≤ 6.12.* (unaffected, semver) ≥ 6.18.30; ≤ 6.18.* (unaffected, semver) ≥ 7.0.7; ≤ 7.0.* (unaffected, semver) ≥ 7.1; ≤ * (unaffected, original_commit_for_fix) Other versions: affected |
CNA: Linux |
| SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) Siemens |
≥ V3.1.6; < * (affected, custom)
Other versions: unknown |
ADP: siemens-SADP |
| SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) Siemens |
≥ V3.1.7; < * (affected, custom)
Other versions: unknown |
ADP: siemens-SADP |
| SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) Siemens |
≥ V3.1.6; < * (affected, custom)
Other versions: unknown |
ADP: siemens-SADP |
| SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) Siemens |
≥ V3.1.7; < * (affected, custom)
Other versions: unknown |
ADP: siemens-SADP |
| SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) Siemens |
≥ V3.1.6; < * (affected, custom)
Other versions: unknown |
ADP: siemens-SADP |
| SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) Siemens |
≥ V3.1.7; < * (affected, custom)
Other versions: unknown |
ADP: siemens-SADP |
| SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) Siemens |
≥ V3.1.6; < * (affected, custom)
Other versions: unknown |
ADP: siemens-SADP |
| SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) Siemens |
≥ V3.1.7; < * (affected, custom)
Other versions: unknown |
ADP: siemens-SADP |
| SIMATIC S7-1500 TM MFP - GNU/Linux subsystem Siemens |
≥ 0; < * (affected, custom)
Other versions: unknown |
ADP: siemens-SADP |
| SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) Siemens |
≥ V3.1.6; < * (affected, custom)
Other versions: unknown |
ADP: siemens-SADP |
| SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) Siemens |
≥ V3.1.7; < * (affected, custom)
Other versions: unknown |
ADP: siemens-SADP |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 7.8 high |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | CNA: Linux |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://git.kernel.org/stable/c/3d6fb8a7690c23e3213c4b008f64d89a44b98737CNA: Linux
- https://git.kernel.org/stable/c/640b4c00fb0e2920327435f6176cbefc3c546165CNA: Linux
- https://git.kernel.org/stable/c/7b2800ba5f5f77a8ee7f4cbadb19cf1264597a34CNA: Linux
- https://git.kernel.org/stable/c/6f49f94f3b11fe8bff1bf2a054143789e76aaf17CNA: Linux
- https://git.kernel.org/stable/c/9756b3db5db6c2f5eccb32dddbd88eb4c54f575eCNA: Linux
- https://git.kernel.org/stable/c/c1fa0bb633e4a6b11e83ffc57fa5abe8ebb87891CNA: Linux
- https://project-zero.issues.chromium.org/issues/510793286CNA: Linux
- https://cert-portal.siemens.com/productcert/html/ssa-019113.htmlADP: siemens-SADP
- https://cert-portal.siemens.com/productcert/html/ssa-457936.htmlADP: siemens-SADP
- https://cert-portal.siemens.com/productcert/html/ssa-784472.htmlADP: siemens-SADP
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