CVE-2026-53243
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.
Executive briefing
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Evidence confidence: Not assessed Evidence-derived, not an exploitability verdict
Severity & attack characteristics
CVSS vector:CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
No CVSS vector is currently available in the source record.
Technical explanation & impact
Technical root-cause details are not available in the current source record.
Assess the impact using the published CVSS metrics and the affected vendor component.
Affected products and versions
NVD has not supplied machine-readable vulnerable CPE product/version entries for this CVE. This is an information gap, not proof that no products are affected. Check the vendor advisory references below.
Remediation & validation
- Identify exposure by comparing the affected product and version ranges with your asset inventory, SBOM and externally exposed services.
- Review the linked vendor security advisory or patch notes. Upgrade to a vendor-confirmed fixed release; do not infer a fixed version from the CVE description.
- Until patched, consider restricting network access or disabling the affected feature where operationally safe. These are temporary controls, not a substitute for a vendor fix.
- Validate the remediation with a version check and vulnerability rescan, then retain change evidence.
No fixed version is displayed unless it is explicitly established by a vendor advisory. Follow the vendor's release notes for exact product and branch applicability.