Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: rseq: Fix using an uninitialized stack variable in rseq_exit_user_update() There is an bug in which an uninitialized stack variable is used in rseq_exit_user_update() as reported by syzbot: BUG: KMSAN: kernel-infoleak in rseq_set_ids_get_csaddr include/linux/rseq_entry.h:502 [inline] The local variable: struct rseq_ids ids = { .cpu_id = task_cpu(t), .mm_cid = task_mm_cid(t), .node_id = cpu_to_node(ids.cpu_id), }; According to the C standard, the evaluation order of expressions in an initializer list is indeterminately sequenced. The compiler (Clang, in this KMSAN build) evaluates `cpu_to_node(ids.cpu_id)` *before* `ids.cpu_id` is initialized with `task_cpu(t)`. This is fixed by moving the assignment of ids.node_id outside the structure initialization.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux Kernel | >= 7.0.10, < 7.0.13 |
Related Weaknesses (CWE)
References
- https://git.kernel.org/stable/c/6d99479799c69c3cb588fcda19c81d8f61d64ecdPatch
- https://git.kernel.org/stable/c/e12d20a63b61aaf9de4772effccf42cc9a003e58Patch
FAQ
What is CVE-2026-53243?
CVE-2026-53243 is a vulnerability with a CVSS score of 5.5 (MEDIUM). In the Linux kernel, the following vulnerability has been resolved: rseq: Fix using an uninitialized stack variable in rseq_exit_user_update() There is an bug in which an uninitialized stack variabl...
How severe is CVE-2026-53243?
CVE-2026-53243 has been rated MEDIUM with a CVSS base score of 5.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-53243?
Check the references section above for vendor advisories and patch information. Affected products include: Linux Linux Kernel.