Vulnerability · Published May 18, 2026 · Assigned by Mattermost
CVE-2026-6345Prevent password disclosure and force reset during Slack import
Medium 6.5
In plain English
A medium-severity security flaw 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 0.2% (higher than 14% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)6.5Medium
Exploit odds (30 days)0.2%top 86.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail prevent disclosure of created user password which allows a malicious attacker to impersonate a user via the use of some of those passwords.. Mattermost Advisory ID: MMSA-2026-00614
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-2026-5727 |
| Go | github.com/mattermost/mattermost-server | 5.3.2-0.20260311102650-3057ae7e83e9 | GHSA-wvgv-4fc3-2rcp |
| Go | github.com/mattermost/mattermost-server/v5 | no fix listed | GO-2026-5727 |
| Go | github.com/mattermost/mattermost-server/v6 | no fix listed | GO-2026-5727 |
| Go | github.com/mattermost/mattermost/server/v8 | 11.5.2 | GHSA-wvgv-4fc3-2rcp |
| Go | github.com/mattermost/mattermost/server/v8 | 8.0.0-20260311102650-3057ae7e83e9 | GO-2026-5727 |
| Go | github.com/mattermost/mattermost/server/v8 | 10.11.14 | GHSA-wvgv-4fc3-2rcp |
| Go | github.com/mattermost/mattermost/server/v8 | 11.4.4 | GHSA-wvgv-4fc3-2rcp |
| Go | github.com/mattermost/mattermost/server/v8 | 8.0.0-20260311102650-3057ae7e83e9 | GHSA-wvgv-4fc3-2rcp |
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-522 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
References
- MMSA-2026-00614 vendor-advisory