CVE-2026-5132
mediumMattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to limit size of unpacked SDP messages compressed with zlib,…
Vendor / product: Mattermost — mattermost server
Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to limit size of unpacked SDP messages compressed with zlib, which allows attacker to deny service or crash server via sending many SDP messages that unpack to large size.. Mattermost Advisory ID: MMSA-2026-00643
CVSS
6.5
6.5 (CVSS v3.1)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Severity source: NVD CVSS v3.1 (responsibledisclosure@mattermost.com)
Timeline (UTC)
Published: 2026-09-14 11:17
Modified: 2026-10-07 15:43
NVD status: Analyzed
Last synced 2 days ago
Verified against the source API 2026-10-27 06:52 UTC
Exploitation
Not listed in CISA KEV (as of last catalog sync)
Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).
Affected products
mattermost / mattermost_server ≥10.11.0 <10.11.23, ≥11.7.0 <11.7.8, ≥11.8.0 <11.8.5, ≥11.9.0 <11.9.1
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
Vendor advisory: https://mattermost.com/security-updates
References
- https://mattermost.com/security-updates responsibledisclosure@mattermost.com
Data sources
NVD CVE API 2.0 — fetched 2026-10-27 06:52 UTC · record ↗