CVE-2026-15754

MEDIUMPre-NVD 4.24.2—
EchelonGraph scoreHIGH confidence

Score 4.2 from GitHub Security Advisory published 2026-08-17. a secondary CVSS source baseline 4.2; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
4.2EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.2Exploit: None knownExposed: 0

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

Mattermost versions 11.7.x <= 11.7.6, 11.8.x <= 11.8.3 The access control policy unassign endpoint fails to re-validate that each target channel still belongs to the requesting admin's team, which allows an authenticated team administrator to remove ABAC (attribute-based access control) policy assignments from channels outside their team via the policy unassign API after a channel has been moved to another team.. Mattermost Advisory ID: MMSA-2026-00718

CVSS v3
4.2
EG Score
4.2(high)
EG Risk
19(Track)
EG Risk 19/100SSVC: 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
Severity42% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
5%
KEV
Not listed

Published

August 17, 2026

Last Modified

August 18, 2026

Advisory Details (1)

Auto-updated Aug 17, 2026
No patch confirmed yet.
generic

Security Updates

https://mattermost.com/security-updates

Vendor Advisories for CVE-2026-15754(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 16× in last 7d / 16× 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. 2026-08-20 22:55 UTCEPSS rescore
  2. 2026-08-20 18:27 UTCGHSA enrichment
  3. 2026-08-19 19:35 UTCEG score recompute
  4. 2026-08-19 19:35 UTCGHSA enrichment
  5. 2026-08-19 17:03 UTCEPSS rescore
  6. 2026-08-18 20:43 UTCGHSA enrichment
  7. 2026-08-18 15:15 UTCEG score recompute
  8. 2026-08-18 15:15 UTCGHSA enrichment
  9. 2026-08-18 13:48 UTCEPSS rescore
  10. 2026-08-17 16:22 UTCEG score recompute
  11. 2026-08-17 16:22 UTCGHSA enrichment
  12. 2026-08-17 16:10 UTCEG score recompute
  13. 2026-08-17 16:10 UTCGHSA enrichment
  14. 2026-08-17 15:20 UTCEG score recompute
  15. 2026-08-17 14:44 UTCEG score recompute
  16. 2026-08-17 14:44 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-15754?
CVE-2026-15754 is a medium vulnerability published on August 17, 2026. Mattermost versions 11.7.x <= 11.7.6, 11.8.x <= 11.8.3 The access control policy unassign endpoint fails to re-validate that each target channel still belongs to the requesting admin's team, which allows an authenticated team administrator to remove ABAC (attribute-based access control) policy…
When was CVE-2026-15754 disclosed?
CVE-2026-15754 was first published in the National Vulnerability Database on August 17, 2026, with the most recent update on August 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-15754 actively exploited?
CVE-2026-15754 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 95.3% of all scored CVEs.
What is the CVSS score of CVE-2026-15754?
CVE-2026-15754 has a CVSS v3 base score of 4.2 (NVD).
How do I remediate CVE-2026-15754?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-15754, 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

Explore the affected products and dependency analysis for CVE-2026-15754

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