CVE-2026-16049

MEDIUMPre-NVD 4.34.3—
EchelonGraph scoreMEDIUM 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 — 3 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: 0.3%CVSS: 4.3Exploit: None knownExposed services: Not assessed

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

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
4.3MEDIUMmedium confidence
EG Risk
19
EG Risk 19/100CISA SSVC

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%
CISA SSVC: Track at every mission impact level.
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.
EPSS PROB
0.3%
EPSS %ILE
19th
KEV
Not listed

CISA SSVCTrack at every mission impact level.

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

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 15× in last 7d / 67× 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.

Showing the most recent 100 of 127 total refreshes for this CVE.

  1. 2026-10-04 23:21 UTCEPSS rescore
  2. 2026-10-04 21:50 UTCGHSA enrichment
  3. 2026-10-03 17:49 UTCEG score recompute
  4. 2026-10-03 17:49 UTCGHSA enrichment
  5. 2026-10-03 14:25 UTCEPSS rescore
  6. 2026-10-02 15:46 UTCEG score recompute
  7. 2026-10-02 15:46 UTCGHSA enrichment
  8. 2026-10-01 19:49 UTCEPSS rescore
  9. 2026-10-01 10:45 UTCEG score recompute
  10. 2026-10-01 10:45 UTCGHSA enrichment
  11. 2026-09-30 15:02 UTCEPSS rescore
  12. 2026-09-30 10:02 UTCEG score recompute
  13. 2026-09-30 10:02 UTCGHSA enrichment
  14. 2026-09-29 15:20 UTCEPSS rescore
  15. 2026-09-28 13:51 UTCEPSS rescore
  16. 2026-09-28 08:49 UTCEG score recompute
  17. 2026-09-28 08:49 UTCGHSA enrichment
  18. 2026-09-27 13:47 UTCEPSS rescore
  19. 2026-09-27 08:17 UTCEG score recompute
  20. 2026-09-27 08:17 UTCGHSA enrichment
  21. 2026-09-26 15:58 UTCEPSS rescore
  22. 2026-09-24 16:14 UTCEG score recompute
  23. 2026-09-24 16:14 UTCGHSA enrichment
  24. 2026-09-23 14:20 UTCEG score recompute
  25. 2026-09-23 14:20 UTCGHSA enrichment
Show 75 more
  1. 2026-09-22 13:43 UTCEG score recompute
  2. 2026-09-22 13:43 UTCGHSA enrichment
  3. 2026-09-21 13:11 UTCEG score recompute
  4. 2026-09-21 13:11 UTCGHSA enrichment
  5. 2026-09-20 12:39 UTCEG score recompute
  6. 2026-09-20 12:39 UTCGHSA enrichment
  7. 2026-09-19 10:59 UTCEG score recompute
  8. 2026-09-19 10:59 UTCGHSA enrichment
  9. 2026-09-18 19:27 UTCEPSS rescore
  10. 2026-09-18 08:39 UTCEG score recompute
  11. 2026-09-18 08:39 UTCGHSA enrichment
  12. 2026-09-17 08:06 UTCEG score recompute
  13. 2026-09-17 08:06 UTCGHSA enrichment
  14. 2026-09-16 14:07 UTCEPSS rescore
  15. 2026-09-16 07:33 UTCEG score recompute
  16. 2026-09-16 07:32 UTCGHSA enrichment
  17. 2026-09-16 05:14 UTCEPSS rescore
  18. 2026-09-15 06:59 UTCEG score recompute
  19. 2026-09-15 06:59 UTCGHSA enrichment
  20. 2026-09-14 06:26 UTCEG score recompute
  21. 2026-09-14 06:26 UTCGHSA enrichment
  22. 2026-09-13 16:46 UTCEPSS rescore
  23. 2026-09-13 05:53 UTCEG score recompute
  24. 2026-09-13 05:53 UTCGHSA enrichment
  25. 2026-09-12 15:00 UTCEPSS rescore
  26. 2026-09-12 05:21 UTCEG score recompute
  27. 2026-09-12 05:21 UTCGHSA enrichment
  28. 2026-09-11 14:52 UTCEPSS rescore
  29. 2026-09-11 09:36 UTCEPSS rescore
  30. 2026-09-11 04:48 UTCEG score recompute
  31. 2026-09-11 04:48 UTCGHSA enrichment
  32. 2026-09-10 09:34 UTCEPSS rescore
  33. 2026-09-10 04:15 UTCGHSA enrichment
  34. 2026-09-09 03:41 UTCEG score recompute
  35. 2026-09-09 03:41 UTCGHSA enrichment
  36. 2026-09-08 22:00 UTCEPSS rescore
  37. 2026-09-07 16:01 UTCEPSS rescore
  38. 2026-09-07 10:38 UTCEG score recompute
  39. 2026-09-07 10:37 UTCGHSA enrichment
  40. 2026-09-06 13:47 UTCEPSS rescore
  41. 2026-09-06 10:03 UTCEG score recompute
  42. 2026-09-06 10:03 UTCGHSA enrichment
  43. 2026-09-05 09:30 UTCEG score recompute
  44. 2026-09-05 09:30 UTCGHSA enrichment
  45. 2026-09-04 08:57 UTCEG score recompute
  46. 2026-09-04 08:57 UTCGHSA enrichment
  47. 2026-09-04 05:06 UTCEPSS rescore
  48. 2026-09-03 08:24 UTCEG score recompute
  49. 2026-09-03 08:24 UTCGHSA enrichment
  50. 2026-09-02 14:11 UTCEPSS rescore
  51. 2026-09-02 07:50 UTCEG score recompute
  52. 2026-09-02 07:50 UTCGHSA enrichment
  53. 2026-09-01 13:53 UTCEPSS rescore
  54. 2026-09-01 07:18 UTCEG score recompute
  55. 2026-09-01 07:17 UTCGHSA enrichment
  56. 2026-09-01 04:39 UTCEPSS rescore
  57. 2026-08-31 06:43 UTCEG score recompute
  58. 2026-08-31 06:43 UTCGHSA enrichment
  59. 2026-08-30 19:17 UTCEPSS rescore
  60. 2026-08-30 06:11 UTCEG score recompute
  61. 2026-08-30 06:11 UTCGHSA enrichment
  62. 2026-08-30 01:22 UTCEPSS rescore
  63. 2026-08-29 05:39 UTCEG score recompute
  64. 2026-08-29 05:39 UTCGHSA enrichment
  65. 2026-08-28 21:41 UTCEPSS rescore
  66. 2026-08-27 20:36 UTCEG score recompute
  67. 2026-08-27 20:36 UTCGHSA enrichment
  68. 2026-08-27 14:25 UTCEPSS rescore
  69. 2026-08-26 20:02 UTCEG score recompute
  70. 2026-08-26 20:02 UTCGHSA enrichment
  71. 2026-08-26 14:46 UTCEPSS rescore
  72. 2026-08-25 19:29 UTCEG score recompute
  73. 2026-08-25 19:29 UTCGHSA enrichment
  74. 2026-08-25 13:48 UTCEPSS rescore
  75. 2026-08-24 18:56 UTCEG score recompute

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 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 0.3% probability of exploitation in the next 30 days (19th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-16049?
CVE-2026-16049 has a CVSS base score of 4.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-16049?
No fix for CVE-2026-16049 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2026-16049 are linked in the Vendor Advisories panel on this page.

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