Vulnerability · Published Mar 26, 2026 · Assigned by Mattermost
CVE-2026-3114Zip Bomb Denial of Service via Unrestricted Archive Decompression
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 0.4% (higher than 29% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to validate decompressed archive entry sizes during file extraction which allows authenticated users with file upload permissions to cause a denial of service via crafted zip archives containing highly compressed entries (zip bombs) that exhaust server memory.. Mattermost Advisory ID: MMSA-2026-00598
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/mattermost/mattermost-server | 10.11.12+incompatible, 11.2.4+incompatible, 11.3.2+incompatible, 11.4.1+incompatible | GO-2026-5663 |
| Go | github.com/mattermost/mattermost-server/v5 | no fix listed | GO-2026-5663 |
| Go | github.com/mattermost/mattermost-server/v6 | no fix listed | GO-2026-5663 |
| Go | github.com/mattermost/mattermost/server/v8 | 10.11.12 | GHSA-vhgh-g7x8-4rx8 |
| Go | github.com/mattermost/mattermost/server/v8 | 8.0.0-20260217110922-b7d4a1f1f59b | GHSA-vhgh-g7x8-4rx8 |
| Go | github.com/mattermost/mattermost/server/v8 | 11.4.1 | GHSA-vhgh-g7x8-4rx8 |
| Go | github.com/mattermost/mattermost/server/v8 | 8.0.0-20260217110922-b7d4a1f1f59b | GO-2026-5663 |
| Go | github.com/mattermost/mattermost/server/v8 | 11.3.2 | GHSA-vhgh-g7x8-4rx8 |
| Go | github.com/mattermost/mattermost/server/v8 | 11.2.4 | GHSA-vhgh-g7x8-4rx8 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mattermost | Mattermost | 11.4.0 – through 11.4.011.3.0 – through 11.3.111.2.0 – through 11.2.310.11.0 – through 10.11.11 |
Weakness: CWE-409 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
References
- MMSA-2026-00598 vendor-advisory