CVE-2026-53243
5.5 · MEDIUMOverview
CVE-2026-53243 is a medium-severity vulnerability affecting linux linux_kernel. It was published on June 25, 2026 and has a CVSS 3.1 base score of 5.5 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
Technical 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.
Remediation
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| linux | linux_kernel | >= 7.0.10, < 7.0.13 | Affected |
Frequently Asked Questions
What is CVE-2026-53243?
CVE-2026-53243 is a medium-severity vulnerability affecting linux linux_kernel. It was published on June 25, 2026 and has a CVSS 3.1 base score of 5.5 (MEDIUM).
How severe is CVE-2026-53243?
This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2026-53243?
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-53243?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-53243 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
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