CVE-2026-53243

MEDIUMNVD 5.55.5—
EchelonGraph scoreHIGH confidence

Score 5.5 from GitHub Security Advisory published 2026-06-25. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.5Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 v3
5.5
EG Score
5.5(high)
EG Risk
29(Track)
EG Risk 29/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity55% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
1.4%
KEV
Not listed

Published

June 25, 2026

Last Modified

July 7, 2026

Advisory Details (2)

Auto-updated Jul 8, 2026
No patch confirmed yet.
generic

rseq: Fix using an uninitialized stack variable in rseq_exit_user_update() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/e12d20a63b61aaf9de4772effccf42cc9a003e58
generic

rseq: Fix using an uninitialized stack variable in rseq_exit_user_update() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/6d99479799c69c3cb588fcda19c81d8f61d64ecd

Vendor Advisories for CVE-2026-53243(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 9× in last 7d / 54× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-24 14:18 UTCEPSS rescore
  2. 2026-07-23 14:18 UTCEPSS rescore
  3. 2026-07-23 03:19 UTCEG score recompute
  4. 2026-07-22 14:08 UTCEPSS rescore
  5. 2026-07-20 17:08 UTCEPSS rescore
  6. 2026-07-19 14:31 UTCEPSS rescore
  7. 2026-07-19 14:31 UTCEPSS rescore
  8. 2026-07-19 02:29 UTCEPSS rescore
  9. 2026-07-18 10:04 UTCEPSS rescore
  10. 2026-07-16 17:03 UTCEPSS rescore
  11. 2026-07-16 11:01 UTCGHSA enrichment
  12. 2026-07-15 16:57 UTCEPSS rescore
  13. 2026-07-15 16:57 UTCEPSS rescore
  14. 2026-07-15 12:01 UTCGHSA enrichment
  15. 2026-07-14 13:16 UTCGHSA enrichment
  16. 2026-07-13 22:31 UTCEPSS rescore
  17. 2026-07-13 14:30 UTCGHSA enrichment
  18. 2026-07-13 06:13 UTCEPSS rescore
  19. 2026-07-13 06:13 UTCEPSS rescore
  20. 2026-07-12 15:43 UTCGHSA enrichment
  21. 2026-07-12 05:46 UTCEPSS rescore
  22. 2026-07-11 16:57 UTCGHSA enrichment
  23. 2026-07-10 18:12 UTCEG score recompute▲ 5.50
  24. 2026-07-10 18:11 UTCGHSA enrichment
  25. 2026-07-09 19:10 UTCEPSS rescore
Show 29 more
  1. 2026-07-09 19:10 UTCEPSS rescore
  2. 2026-07-08 15:16 UTCEPSS rescore
  3. 2026-07-08 15:16 UTCEPSS rescore
  4. 2026-07-07 22:30 UTCNVD updateCVSS v3 → 5.5 · severity → MEDIUM
  5. 2026-07-07 16:43 UTCGHSA enrichment
  6. 2026-07-07 13:46 UTCEPSS rescore
  7. 2026-07-07 13:46 UTCEPSS rescore
  8. 2026-07-06 16:27 UTCEPSS rescore
  9. 2026-07-06 16:27 UTCEPSS rescore
  10. 2026-07-06 02:23 UTCEPSS rescore
  11. 2026-07-06 02:23 UTCEPSS rescore
  12. 2026-07-05 02:31 UTCEPSS rescore
  13. 2026-07-05 02:30 UTCEPSS rescore
  14. 2026-07-04 14:24 UTCGHSA enrichment
  15. 2026-07-04 06:31 UTCEPSS rescore
  16. 2026-07-04 06:31 UTCEPSS rescore
  17. 2026-07-01 15:07 UTCEPSS rescore
  18. 2026-07-01 12:59 UTCGHSA enrichment
  19. 2026-06-30 23:22 UTCEPSS rescore
  20. 2026-06-29 14:06 UTCEPSS rescore
  21. 2026-06-29 14:06 UTCEPSS rescore
  22. 2026-06-28 14:07 UTCEPSS rescore
  23. 2026-06-28 11:32 UTCGHSA enrichment
  24. 2026-06-28 04:56 UTCEPSS rescore
  25. 2026-06-28 04:56 UTCEPSS rescore
  26. 2026-06-27 03:08 UTCEPSS rescore
  27. 2026-06-25 13:49 UTCEPSS rescore
  28. 2026-06-25 10:06 UTCEG score recompute
  29. 2026-06-25 10:06 UTCGHSA enrichment

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-53243?
CVE-2026-53243 is a medium vulnerability published on June 25, 2026. In the Linux kernel, the following vulnerability has been resolved: rseq: Fix using an uninitialized stack variable in rseqexituser_update() There is an bug in which an uninitialized stack variable is used in rseqexituser_update() as reported by syzbot: BUG: KMSAN: kernel-infoleak in…
When was CVE-2026-53243 disclosed?
CVE-2026-53243 was first published in the National Vulnerability Database on June 25, 2026, with the most recent update on July 7, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-53243 actively exploited?
CVE-2026-53243 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-53243?
CVE-2026-53243 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-53243?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-53243, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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