CVE-2026-15754

MEDIUMPre-NVD 4.24.2—
EchelonGraph scoreMEDIUM 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 — 3 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: 0.2%CVSS: 4.2Exploit: 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 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
4.2MEDIUMmedium 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
Severity42% × 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
0.2%
EPSS %ILE
14th
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-2026-15754(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 / 69× 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 128 total refreshes for this CVE.

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

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 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 0.2% probability of exploitation in the next 30 days (14th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-15754?
CVE-2026-15754 has a CVSS base score of 4.2 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-15754?
No fix for CVE-2026-15754 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-2026-15754 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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