CVE-2026-6673

MEDIUMPre-NVD 6.46.4—
EchelonGraph scoreHIGH confidence

Score 6.4 from GitHub Security Advisory published 2026-06-22. a secondary CVSS source baseline 6.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
6.4
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.4Exploit: NoneExposed: 0

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

Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to authenticate Atlassian Connect installed callbacks, allowing a remote unauthenticated attacker to inject a rogue sharedSecret and disrupt the Jira integration via POST to /ac/installed during the pending-install window.. Mattermost Advisory ID: MMSA-2026-00654

CVSS v3
6.4
EG Score
6.4(high)
EPSS
7.4%
KEV
Not listed

Published

June 22, 2026

Last Modified

June 23, 2026

Advisory Details (1)

Auto-updated Jun 22, 2026
No patch confirmed yet.
generic

Security Updates

https://mattermost.com/security-updates

Vendor Advisories for CVE-2026-6673(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 22× in last 7d / 46× 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. 2026-07-06 16:27 UTCEPSS rescore
  2. 2026-07-06 16:27 UTCEPSS rescore
  3. 2026-07-06 08:39 UTCEG score recompute
  4. 2026-07-06 08:39 UTCGHSA enrichment
  5. 2026-07-06 02:23 UTCEPSS rescore
  6. 2026-07-06 02:23 UTCEPSS rescore
  7. 2026-07-05 07:18 UTCEG score recompute
  8. 2026-07-05 07:18 UTCGHSA enrichment
  9. 2026-07-05 02:31 UTCEPSS rescore
  10. 2026-07-05 02:30 UTCEPSS rescore
  11. 2026-07-04 06:31 UTCEPSS rescore
  12. 2026-07-04 06:31 UTCEPSS rescore
  13. 2026-07-04 06:06 UTCEG score recompute
  14. 2026-07-04 06:06 UTCGHSA enrichment
  15. 2026-07-03 04:54 UTCEG score recompute
  16. 2026-07-03 04:54 UTCGHSA enrichment
  17. 2026-07-02 03:43 UTCEG score recompute
  18. 2026-07-02 03:43 UTCGHSA enrichment
  19. 2026-07-01 15:07 UTCEPSS rescore
  20. 2026-07-01 02:32 UTCEG score recompute
  21. 2026-07-01 02:32 UTCGHSA enrichment
  22. 2026-06-30 23:22 UTCEPSS rescore
  23. 2026-06-30 01:21 UTCEG score recompute
  24. 2026-06-30 01:21 UTCGHSA enrichment
  25. 2026-06-29 14:06 UTCEPSS rescore
Show 21 more
  1. 2026-06-29 00:10 UTCEG score recompute
  2. 2026-06-29 00:10 UTCGHSA enrichment
  3. 2026-06-28 14:07 UTCEPSS rescore
  4. 2026-06-28 04:56 UTCEPSS rescore
  5. 2026-06-27 22:59 UTCEG score recompute
  6. 2026-06-27 22:59 UTCGHSA enrichment
  7. 2026-06-27 03:08 UTCEPSS rescore
  8. 2026-06-26 21:48 UTCEG score recompute
  9. 2026-06-26 21:48 UTCGHSA enrichment
  10. 2026-06-25 20:32 UTCEG score recompute
  11. 2026-06-25 20:32 UTCGHSA enrichment
  12. 2026-06-25 13:50 UTCEPSS rescore
  13. 2026-06-24 19:21 UTCEG score recompute
  14. 2026-06-24 19:21 UTCGHSA enrichment
  15. 2026-06-24 14:05 UTCEPSS rescore
  16. 2026-06-23 21:33 UTCEPSS rescore
  17. 2026-06-23 21:33 UTCEPSS rescore
  18. 2026-06-23 16:51 UTCEG score recompute
  19. 2026-06-23 16:51 UTCGHSA enrichment
  20. 2026-06-22 15:37 UTCEG score recompute
  21. 2026-06-22 15:37 UTCGHSA enrichment

Frequently asked(5)

What is CVE-2026-6673?
CVE-2026-6673 is a medium vulnerability published on June 22, 2026. Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to authenticate Atlassian Connect installed callbacks, allowing a remote unauthenticated attacker to inject a rogue sharedSecret and disrupt the Jira integration via POST to /ac/installed during the…
When was CVE-2026-6673 disclosed?
CVE-2026-6673 was first published in the National Vulnerability Database on June 22, 2026, with the most recent update on June 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-6673 actively exploited?
CVE-2026-6673 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 7.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-6673?
CVE-2026-6673 has a CVSS v3 base score of 6.4 (NVD).
How do I remediate CVE-2026-6673?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-6673, 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-2026-6673

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