CVE-2026-6347

HIGHNVD 7.67.6—
EchelonGraph scoreMEDIUM confidence

Score 7.6 from GitHub Security Advisory (severity: HIGH) published 2026-05-18. NVD baseline CVSS 7.6; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
7.6
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.6Exploit: NoneExposed: 0

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

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to sanitize sensitive configuration fields in the Mattermost Calls plugin which allows an attacker with access to a support packet to obtain TURN server credentials via the plaintext values present in the exported plugin configuration.. Mattermost Advisory ID: MMSA-2026-00605

CVSS v3
7.6
EG Score
7.6(medium)
EPSS
17.0%
KEV
Not listed

Published

May 18, 2026

Last Modified

May 18, 2026

Advisory Details (1)

Auto-updated May 18, 2026
No patch confirmed yet.
generic

Security Updates

https://mattermost.com/security-updates

Vendor Advisories for CVE-2026-6347(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-calls—1.12.0-rc2—
github.com/mattermost/mattermost-server—11.4.4—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 62× 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 116 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
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  9. 2026-07-06 16:27 UTCEPSS rescore
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  11. 2026-07-06 02:23 UTCEPSS rescore
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  15. 2026-07-04 06:31 UTCEPSS rescore
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  17. 2026-07-01 15:07 UTCEPSS rescore
  18. 2026-06-30 23:22 UTCEPSS rescore
  19. 2026-06-29 21:11 UTCEG score recompute
  20. 2026-06-29 14:06 UTCEPSS rescore
  21. 2026-06-28 14:07 UTCEPSS rescore
  22. 2026-06-28 08:40 UTCEG score recompute
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  24. 2026-06-27 21:25 UTCEG score recompute
  25. 2026-06-27 07:44 UTCEG score recompute
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  1. 2026-06-27 03:08 UTCEPSS rescore
  2. 2026-06-26 19:57 UTCEG score recompute
  3. 2026-06-26 05:33 UTCEG score recompute
  4. 2026-06-25 18:21 UTCEG score recompute
  5. 2026-06-25 13:50 UTCEPSS rescore
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  7. 2026-06-23 21:33 UTCEPSS rescore
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  17. 2026-06-18 17:52 UTCEPSS rescore
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  19. 2026-06-18 02:28 UTCEG score recompute
  20. 2026-06-17 17:53 UTCEPSS rescore
  21. 2026-06-17 13:17 UTCEG score recompute
  22. 2026-06-16 22:10 UTCEG score recompute
  23. 2026-06-16 17:53 UTCEPSS rescore
  24. 2026-06-16 10:56 UTCEG score recompute
  25. 2026-06-15 23:14 UTCEG score recompute
  26. 2026-06-15 17:49 UTCEPSS rescore
  27. 2026-06-15 17:49 UTCEPSS rescore
  28. 2026-06-15 00:34 UTCEG score recompute
  29. 2026-06-14 23:18 UTCEPSS rescore
  30. 2026-06-14 13:23 UTCEG score recompute
  31. 2026-06-14 02:07 UTCEG score recompute
  32. 2026-06-13 23:00 UTCEPSS rescore
  33. 2026-06-13 14:55 UTCEG score recompute
  34. 2026-06-13 00:22 UTCEG score recompute
  35. 2026-06-12 23:12 UTCEPSS rescore
  36. 2026-06-12 23:12 UTCEPSS rescore
  37. 2026-06-12 13:11 UTCEG score recompute
  38. 2026-06-12 01:56 UTCEG score recompute
  39. 2026-06-11 14:46 UTCEG score recompute
  40. 2026-06-11 14:00 UTCEPSS rescore
  41. 2026-06-11 03:34 UTCEG score recompute
  42. 2026-06-10 22:19 UTCEPSS rescore
  43. 2026-06-10 16:23 UTCEG score recompute
  44. 2026-06-10 13:22 UTCEPSS rescore
  45. 2026-06-10 05:13 UTCEG score recompute
  46. 2026-06-09 18:02 UTCEG score recompute
  47. 2026-06-09 06:52 UTCEG score recompute
  48. 2026-06-08 19:40 UTCEG score recompute
  49. 2026-06-08 14:17 UTCEPSS rescore
  50. 2026-06-08 05:01 UTCEG score recompute
  51. 2026-06-07 17:51 UTCEG score recompute
  52. 2026-06-07 15:25 UTCEPSS rescore
  53. 2026-06-07 06:40 UTCEG score recompute
  54. 2026-06-06 19:29 UTCEG score recompute
  55. 2026-06-06 13:47 UTCEPSS rescore
  56. 2026-06-06 08:18 UTCEG score recompute
  57. 2026-06-05 22:47 UTCEPSS rescore
  58. 2026-06-05 21:08 UTCEG score recompute
  59. 2026-06-05 09:57 UTCEG score recompute
  60. 2026-06-05 06:10 UTCEPSS rescore
  61. 2026-06-04 22:46 UTCEG score recompute
  62. 2026-06-04 13:12 UTCEPSS rescore
  63. 2026-06-04 11:35 UTCEG score recompute
  64. 2026-06-04 00:24 UTCEG score recompute
  65. 2026-06-03 13:13 UTCEG score recompute
  66. 2026-06-03 02:02 UTCEG score recompute
  67. 2026-06-02 20:13 UTCEPSS rescore
  68. 2026-06-02 14:51 UTCEG score recompute
  69. 2026-06-02 03:40 UTCEG score recompute
  70. 2026-06-01 16:29 UTCEG score recompute
  71. 2026-06-01 13:52 UTCEPSS rescore
  72. 2026-06-01 13:52 UTCEPSS rescore
  73. 2026-06-01 05:18 UTCEG score recompute
  74. 2026-06-01 05:18 UTCGHSA enrichment
  75. 2026-05-31 22:30 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-6347?
CVE-2026-6347 is a high vulnerability published on May 18, 2026. Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to sanitize sensitive configuration fields in the Mattermost Calls plugin which allows an attacker with access to a support packet to obtain TURN server credentials via the plaintext values present in the exported…
When was CVE-2026-6347 disclosed?
CVE-2026-6347 was first published in the National Vulnerability Database on May 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-6347 actively exploited?
CVE-2026-6347 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 17.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-6347?
CVE-2026-6347 has a CVSS v3 base score of 7.6 (NVD).
How do I remediate CVE-2026-6347?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-6347, 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-2026-6347

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