CVE-2026-6340
Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to validate 7zip archive structure before processing which allows an authenticated attacker to cause server memory exhaustion and denial of service via uploading a specially crafted 7zip file with excessive folder declarations.. Mattermost Advisory ID: MMSA-2026-00573
- CVSS 3.1
- 6.5
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - EPSS
- 0.2% chance of exploitation in the next 30 days; higher than 14% of CVEs (scores of 2026-10-25)
- CWE
- CWE-789
- Published
- Modified
- Record from
- the NVD, synced
Affected
- mattermost:mattermost_server
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-cjm8-jxpw-g43m | Go | github.com/mattermost/mattermost/server/v8 | >=11.5.0 <11.5.2 | 11.5.2 |
| GHSA-cjm8-jxpw-g43m | Go | github.com/mattermost/mattermost/server/v8 | >=10.11.0 <10.11.14 | 10.11.14 |
| GHSA-cjm8-jxpw-g43m | Go | github.com/mattermost/mattermost/server/v8 | >=11.4.0 <11.4.4 | 11.4.4 |
| GHSA-cjm8-jxpw-g43m | Go | github.com/mattermost/mattermost/server/v8 | <8.0.0-20260325191733-fb11968f8798 | 8.0.0-20260325191733-fb11968f8798 |
| GHSA-cjm8-jxpw-g43m | Go | github.com/mattermost/mattermost-server | <5.3.2-0.20260325191733-fb11968f8798 | 5.3.2-0.20260325191733-fb11968f8798 |
| GO-2026-5325 | Go | github.com/mattermost/mattermost-server | >=10.11.0+incompatible <10.11.14+incompatible >=11.4.0+incompatible <11.4.4+incompatible >=11.5.0+incompatible <11.5.2+incompatible | 10.11.14+incompatible, 11.4.4+incompatible, 11.5.2+incompatible |
| GO-2026-5325 | Go | github.com/mattermost/mattermost-server/v5 | all versions | no fix published |
| GO-2026-5325 | Go | github.com/mattermost/mattermost-server/v6 | all versions | no fix published |
| GO-2026-5325 | Go | github.com/mattermost/mattermost/server/v8 | <8.0.0-20260325191733-fb11968f8798 | 8.0.0-20260325191733-fb11968f8798 |