CVE-2026-25783
published 2026-03-16CVE-2026-25783: Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to properly validate User-Agent header tokens which allows an authenticated…
medium4.3CVSS 3.1
AVNACLPRLUINSUCNINAL
Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to properly validate User-Agent header tokens which allows an authenticated attacker to cause a request panic via a specially crafted User-Agent header. Mattermost Advisory ID: MMSA-2026-00586
Affected
14 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| github.com | mattermost_mattermost-server | >= 0 < 5.3.2-0.20260129181235-1346cf529aef | 5.3.2-0.20260129181235-1346cf529aef |
| github.com | mattermost_mattermost-server | >= 10.11.0-rc1 < 10.11.11 | 10.11.11 |
| github.com | mattermost_mattermost-server | >= 10.11.0-rc1+incompatible < 10.11.11+incompatible | 10.11.11+incompatible |
| github.com | mattermost_mattermost-server | >= 11.2.0-rc1 < 11.2.3 | 11.2.3 |
| github.com | mattermost_mattermost-server | >= 11.2.0-rc1+incompatible < 11.2.3+incompatible | 11.2.3+incompatible |
| github.com | mattermost_mattermost-server | >= 11.3.0-rc1 < 11.3.1 | 11.3.1 |
| github.com | mattermost_mattermost-server | >= 11.3.0-rc1+incompatible < 11.3.1+incompatible | 11.3.1+incompatible |
| github.com | mattermost_mattermost_server_v8 | >= 0 < 8.0.0-20260129181235-1346cf529aef | 8.0.0-20260129181235-1346cf529aef |
| mattermost | mattermost | 10.11.0 – 10.11.10 | — |
| mattermost | mattermost | 11.2.0 – 11.2.2 | — |
| mattermost | mattermost | 11.3.0 – 11.3.0 | — |
| mattermost | mattermost_server | >= 10.11.0 < 10.11.11 | 10.11.11 |
| mattermost | mattermost_server | >= 11.2.0 < 11.2.3 | 11.2.3 |
| mattermost | mattermost_server | >= 11.3.0 < 11.3.1 | 11.3.1 |