CVSS 3.1
5.7 mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:HCVE-2026-2456
Medium (5.7) in mattermost mattermost server. EPSS 0.2% chance of exploitation in the next 30 days. Fixed in github.com/mattermost/mattermost/server/v8 8.0.0-20260127165411-fe3052073dc6.
Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 Mattermost fails to limit the size of responses from integration action endpoints, which allows an authenticated attacker to cause server memory exhaustion and denial of service via a malicious integration server that returns an arbitrarily large response when a user clicks an interactive message button.. Mattermost Advisory ID: MMSA-2026-00571
Severity
- EPSS
- 0.2% chance of exploitation in the next 30 days; higher than 6% of CVEs (scores of 2026-10-31)
- CWE
- CWE-789
- Published
- Modified
- Record from
- the NVD, synced
Affected
- mattermost:mattermost_server
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-34g8-9fpp-46ch | Go | github.com/mattermost/mattermost/server/v8 | <8.0.0-20260127165411-fe3052073dc6 | 8.0.0-20260127165411-fe3052073dc6 |
| GHSA-34g8-9fpp-46ch | Go | github.com/mattermost/mattermost-server | <5.3.2-0.20260127165411-fe3052073dc6 | 5.3.2-0.20260127165411-fe3052073dc6 |
| GHSA-34g8-9fpp-46ch | Go | github.com/mattermost/mattermost-server | >=10.11.0-rc1 <10.11.11 | 10.11.11 |
| GHSA-34g8-9fpp-46ch | Go | github.com/mattermost/mattermost-server | >=11.2.0-rc1 <11.2.3 | 11.2.3 |
| GHSA-34g8-9fpp-46ch | Go | github.com/mattermost/mattermost-server | >=11.3.0-rc1 <11.3.1 | 11.3.1 |
| GO-2026-4726 | Go | github.com/mattermost/mattermost-server | >=10.11.0-rc1+incompatible <10.11.11+incompatible >=11.2.0-rc1+incompatible <11.2.3+incompatible >=11.3.0-rc1+incompatible <11.3.1+incompatible | 10.11.11+incompatible, 11.2.3+incompatible, 11.3.1+incompatible |
| GO-2026-4726 | Go | github.com/mattermost/mattermost-server/v5 | all versions | no fix published |
| GO-2026-4726 | Go | github.com/mattermost/mattermost-server/v6 | all versions | no fix published |
| GO-2026-4726 | Go | github.com/mattermost/mattermost/server/v8 | <8.0.0-20260127165411-fe3052073dc6 | 8.0.0-20260127165411-fe3052073dc6 |