CVE-2026-4646

MEDIUMPre-NVD 4.34.3—
EchelonGraph scoreMEDIUM confidence

Score 4.3 from GitHub Security Advisory published 2026-05-26. the CNA's CVSS baseline 4.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:github_m, epss, ghsa
4.3
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 4.3Exploit: NoneExposed: 0

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

Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14...

Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate user-supplied input in API request handlers which allows an authenticated attacker to crash the plugin process via a crafted HTTP request to the PR details endpoint.. Mattermost Advisory ID: MMSA-2026-00638

CVSS v3
4.3
EG Score
4.3(medium)
EPSS
16.2%
KEV
Not listed

Published

May 26, 2026

Last Modified

May 26, 2026

Vendor Advisories for CVE-2026-4646(1)

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

Affected Packages

(2 across 1 ecosystem)
Go(2)
PackageVulnerable rangeFixed inDependents
github.com/mattermost/mattermost-plugin-github—1.0.1-0.20260330164815-c2840e980b3c—
github.com/mattermost/mattermost-server11.6.011.6.1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 60× 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 114 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-4646?
CVE-2026-4646 is a medium vulnerability published on May 26, 2026. Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14... Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate user-supplied input in API request handlers which allows an authenticated attacker to crash…
When was CVE-2026-4646 disclosed?
CVE-2026-4646 was first published in the National Vulnerability Database on May 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-4646 actively exploited?
CVE-2026-4646 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 16.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-4646?
CVE-2026-4646 has a CVSS v4.0 base score of 4.3 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-4646?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-4646, 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-2026-4646

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