Vulnerability · Published May 18, 2026 · Assigned by Mattermost
CVE-2026-6346Sensitive credentials exposed in plaintext in Mattermost support packets
High 8.7
In plain English
A high-severity information exposure in Mattermost from Mattermost. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 23% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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 before including them in support packet generation, which allows a Mattermost System Admin or any party with access to a support packet to obtain sensitive credentials in plaintext via downloading a support packet from the System Console.. Mattermost Advisory ID: MMSA-2026-00607
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/mattermost/mattermost-server | 10.11.14+incompatible, 11.4.4+incompatible, 11.5.2+incompatible | GO-2026-5293 |
| Go | github.com/mattermost/mattermost-server | 5.3.2-0.20260326202606-fac92f4a71f3 | GHSA-9p64-jpc7-m2rp |
| Go | github.com/mattermost/mattermost-server/v5 | no fix listed | GO-2026-5293 |
| Go | github.com/mattermost/mattermost-server/v6 | no fix listed | GO-2026-5293 |
| Go | github.com/mattermost/mattermost/server/v8 | 11.5.2 | GHSA-9p64-jpc7-m2rp |
| Go | github.com/mattermost/mattermost/server/v8 | 8.0.0-20260326202606-fac92f4a71f3 | GO-2026-5293 |
| Go | github.com/mattermost/mattermost/server/v8 | 10.11.14 | GHSA-9p64-jpc7-m2rp |
| Go | github.com/mattermost/mattermost/server/v8 | 11.4.4 | GHSA-9p64-jpc7-m2rp |
| Go | github.com/mattermost/mattermost/server/v8 | 8.0.0-20260326202606-fac92f4a71f3 | GHSA-9p64-jpc7-m2rp |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mattermost | Mattermost | 11.5.0 – through 11.5.110.11.0 – through 10.11.1311.4.0 – through 11.4.3 |
Weakness: CWE-200 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N
References
- MMSA-2026-00607 vendor-advisory