CVE-2026-53243
rseq: Fix using an uninitialized stack variable in rseq_exit_user_update()
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.
INFO
Published Date :
June 25, 2026, 9:16 a.m.
Last Modified :
July 7, 2026, 10:21 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update the Linux kernel to the latest version.
- Review kernel source code for similar issues.
- Apply the provided patch to rseq_exit_user_update().
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-53243.
| URL | Resource |
|---|---|
| https://git.kernel.org/stable/c/6d99479799c69c3cb588fcda19c81d8f61d64ecd | Patch |
| https://git.kernel.org/stable/c/e12d20a63b61aaf9de4772effccf42cc9a003e58 | Patch |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-53243 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-53243
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-53243 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-53243 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jul. 07, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-908 Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc6:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 7.0.10 up to (excluding) 7.0.13 Added Reference Type kernel.org: https://git.kernel.org/stable/c/6d99479799c69c3cb588fcda19c81d8f61d64ecd Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/e12d20a63b61aaf9de4772effccf42cc9a003e58 Types: Patch -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jun. 25, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'd242126fd21ab8f1631fdbc8589e43a9d4229f3b', 'lessThan': 'e12d20a63b61aaf9de4772effccf42cc9a003e58', 'versionType': 'git'}, {'status': 'affected', 'version': '82f572449cfe75f12ea985986da60e11f308f77d', 'lessThan': '6d99479799c69c3cb588fcda19c81d8f61d64ecd', 'versionType': 'git'}], 'programFiles': ['include/linux/rseq_entry.h'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '7.0.10', 'lessThan': '7.0.13', 'versionType': 'semver'}], 'programFiles': ['include/linux/rseq_entry.h'], 'defaultStatus': 'unaffected'}] Added 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. Added Reference https://git.kernel.org/stable/c/6d99479799c69c3cb588fcda19c81d8f61d64ecd Added Reference https://git.kernel.org/stable/c/e12d20a63b61aaf9de4772effccf42cc9a003e58