CVE-2026-18938

MEDIUMPre-NVD 6.26.2—
EchelonGraph scoreHIGH confidence

Score 6.2 from GitHub Security Advisory published 2026-08-07. a secondary CVSS source baseline 6.2; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
6.2EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.2Exploit: None knownExposed: 0

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

A flaw was found in p11-kit. A local attacker, or one with equivalent access to a reachable RPC channel, could exploit an integer overflow vulnerability. By sending specially crafted messages, the attacker can cause the system to miscalculate memory allocation for nested attributes. This leads to a memory corruption issue, specifically a heap out-of-bounds write, which can crash the p11-kit RPC parsing process, resulting in a Denial of Service (DoS). This vulnerability is only exploitable on 32 bit systems.

CVSS v3
6.2
EG Score
6.2(high)
EG Risk
28(Track)
EG Risk 28/100SSVC: 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
Severity62% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
1%
KEV
Not listed

Published

August 7, 2026

Last Modified

August 14, 2026

Advisory Details (2)

Auto-updated Aug 7, 2026
Patch available. Sources: redhat.
redhat

2478995 – (CVE-2026-18938) CVE-2026-18938 p11-kit: Integer overflow in RPC attribute-array length calculation can under-allocate nested attribute storage on 32 bit systems

https://bugzilla.redhat.com/show_bug.cgi?id=2478995
redhat Patch Available

CVE-2026-18938 - Red Hat Customer Portal

Affected: Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to a

https://access.redhat.com/security/cve/CVE-2026-18938

Vendor Advisories for CVE-2026-18938(1)

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

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
p11-kit0.23.22-1 ... 0.26.4-1 (33 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
p11-kit0.24.1-2 ... 0.26.4-1 (24 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
p11-kit0.25.10-1 ... 0.26.4-1 (8 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
p11-kit0.25.10-1 ... 0.26.4-1 (8 versions)——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 20× in last 7d / 44× 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. 2026-08-21 08:08 UTCEG score recompute
  2. 2026-08-21 08:08 UTCGHSA enrichment
  3. 2026-08-20 22:55 UTCEPSS rescore
  4. 2026-08-20 06:00 UTCEG score recompute
  5. 2026-08-20 06:00 UTCGHSA enrichment
  6. 2026-08-19 17:03 UTCEPSS rescore
  7. 2026-08-19 03:52 UTCEG score recompute
  8. 2026-08-19 03:52 UTCGHSA enrichment
  9. 2026-08-18 13:48 UTCEPSS rescore
  10. 2026-08-18 01:44 UTCEG score recompute
  11. 2026-08-18 01:44 UTCGHSA enrichment
  12. 2026-08-17 13:47 UTCEPSS rescore
  13. 2026-08-16 23:36 UTCEG score recompute
  14. 2026-08-16 23:36 UTCGHSA enrichment
  15. 2026-08-16 14:56 UTCEPSS rescore
  16. 2026-08-16 02:14 UTCEPSS rescore
  17. 2026-08-15 21:28 UTCEG score recompute
  18. 2026-08-15 21:28 UTCGHSA enrichment
  19. 2026-08-15 01:30 UTCEPSS rescore
  20. 2026-08-14 19:19 UTCGHSA enrichment
  21. 2026-08-14 05:09 UTCEG score recompute
  22. 2026-08-14 05:09 UTCGHSA enrichment
  23. 2026-08-13 22:00 UTCEPSS rescore
  24. 2026-08-13 03:01 UTCEG score recompute
  25. 2026-08-13 03:01 UTCGHSA enrichment
Show 19 more
  1. 2026-08-12 13:50 UTCEPSS rescore
  2. 2026-08-12 00:53 UTCEG score recompute
  3. 2026-08-12 00:53 UTCGHSA enrichment
  4. 2026-08-11 13:42 UTCEPSS rescore
  5. 2026-08-11 00:00 UTCEPSS rescore
  6. 2026-08-10 22:46 UTCGHSA enrichment
  7. 2026-08-09 20:38 UTCEG score recompute
  8. 2026-08-09 20:38 UTCGHSA enrichment
  9. 2026-08-09 13:46 UTCEPSS rescore
  10. 2026-08-08 18:31 UTCEG score recompute
  11. 2026-08-08 18:31 UTCGHSA enrichment
  12. 2026-08-08 16:37 UTCEPSS rescore
  13. 2026-08-07 16:23 UTCEG score recompute
  14. 2026-08-07 16:23 UTCGHSA enrichment
  15. 2026-08-07 15:23 UTCEG score recompute
  16. 2026-08-07 15:23 UTCGHSA enrichment
  17. 2026-08-07 09:22 UTCEG score recompute
  18. 2026-08-07 08:33 UTCEG score recompute
  19. 2026-08-07 08:33 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-18938?
CVE-2026-18938 is a medium vulnerability published on August 7, 2026. A flaw was found in p11-kit. A local attacker, or one with equivalent access to a reachable RPC channel, could exploit an integer overflow vulnerability. By sending specially crafted messages, the attacker can cause the system to miscalculate memory allocation for nested attributes. This leads to a…
When was CVE-2026-18938 disclosed?
CVE-2026-18938 was first published in the National Vulnerability Database on August 7, 2026, with the most recent update on August 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-18938 actively exploited?
CVE-2026-18938 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 98.7% of all scored CVEs.
What is the CVSS score of CVE-2026-18938?
CVE-2026-18938 has a CVSS v3 base score of 6.2 (NVD).
How do I remediate CVE-2026-18938?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-18938, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-18938

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