Medium severity6.4NVD Advisory· Published Jun 22, 2026· Updated Jun 23, 2026
CVE-2026-6673
CVE-2026-6673
Description
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
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
github.com/mattermost/mattermost-serverGo | >= 11.7.0, < 11.7.1 | 11.7.1 |
github.com/mattermost/mattermost-serverGo | >= 11.6.0, < 11.6.3 | 11.6.3 |
github.com/mattermost/mattermost-serverGo | >= 11.5.0, < 11.5.6 | 11.5.6 |
github.com/mattermost/mattermost-serverGo | >= 10.11.0, < 10.11.18 | 10.11.18 |
Affected products
2cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*+ 1 more
- cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*range: >=10.11.0,<10.11.18
- (no CPE)range: <=11.7.0, <=11.6.2, <=11.5.5, <=10.11.17
Patches
Vulnerability mechanics
References
3- github.com/advisories/GHSA-jqgv-39mg-7c2rghsaADVISORY
- mattermost.com/security-updatesnvdVendor AdvisoryWEB
- nvd.nist.gov/vuln/detail/CVE-2026-6673ghsaADVISORY
News mentions
1- Mattermost: Six Vulnerabilities in User Management, Plugins, and Sessions Disclosed TogetherVypr Intelligence · Jun 22, 2026