CVE-2026-16049

MEDIUMPre-NVD 4.34.3—
EchelonGraph scoreHIGH confidence

Score 4.3 from GitHub Security Advisory published 2026-08-17. a secondary CVSS source baseline 4.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 5 sources updated this week
4.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.3Exploit: None knownExposed: 0

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

Mattermost Plugins versions <=11.8 10.20.11 11.5.7.0 _The Mattermost GitLab plugin fails to verify channel permissions when processing API requests with a caller-supplied_ {{post_id}}_, and fails to validate the_ {{web_url}} _parameter against the configured GitLab instance, which allows an authenticated attacker to inject bot-authored messages containing arbitrary URLs into channels they do not have access to via the_ {{createIssue}} _and_ {{attachCommentToIssue}} _API endpoints._ Mattermost Advisory ID: MMSA-2026-00673

CVSS v3
4.3
EG Score
4.3(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
Severity43% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
13%
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-2026-16049(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 18× in last 7d / 18× 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 16:47 UTCEG score recompute
  3. 2026-08-20 16:47 UTCGHSA enrichment
  4. 2026-08-19 17:03 UTCEPSS rescore
  5. 2026-08-19 15:59 UTCGHSA enrichment
  6. 2026-08-18 15:26 UTCEG score recompute
  7. 2026-08-18 15:25 UTCGHSA enrichment
  8. 2026-08-18 13:48 UTCEPSS rescore
  9. 2026-08-17 16:23 UTCEG score recompute
  10. 2026-08-17 16:23 UTCGHSA enrichment
  11. 2026-08-17 16:22 UTCNVD updateCVSS v3 → 4.3 · severity → MEDIUM
  12. 2026-08-17 16:10 UTCEG score recompute
  13. 2026-08-17 16:10 UTCGHSA enrichment
  14. 2026-08-17 16:09 UTCMITRE cvelistV5CVSS v3 → 3.9 · severity → LOW
  15. 2026-08-17 15:20 UTCEG score recompute▲ 0.40
  16. 2026-08-17 15:20 UTCNVD updateCVSS v3 → 4.3 · severity → MEDIUM
  17. 2026-08-17 14:44 UTCEG score recompute
  18. 2026-08-17 14:44 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-16049?
CVE-2026-16049 is a medium vulnerability published on August 17, 2026. Mattermost Plugins versions <=11.8 10.20.11 11.5.7.0 The Mattermost GitLab plugin fails to verify channel permissions when processing API requests with a caller-supplied {{postid}}, and fails to validate the {{weburl}} parameter against the configured GitLab instance, which allows an authenticated…
When was CVE-2026-16049 disclosed?
CVE-2026-16049 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-2026-16049 actively exploited?
CVE-2026-16049 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 87.5% of all scored CVEs.
What is the CVSS score of CVE-2026-16049?
CVE-2026-16049 has a CVSS v3 base score of 4.3 (NVD).
How do I remediate CVE-2026-16049?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-16049, 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-2026-16049

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