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OpenAdvisories
Medium · 6.5 CVE-2026-5132 EUVD-2026-77370GHSA-9c74-gj4h-5458

Unbounded zlib decompression in Calls SDP WebSocket messages

Published Sep 14, 2026 · Updated Sep 14, 2026 · Assigned by Mattermost

Description

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

Affected products

VendorProductAffectedFixed
Mattermost Mattermost 11.9.0 – ≤ 11.9.0, 11.8.0 – ≤ 11.8.4, 11.7.0 – ≤ 11.7.7, 10.11.0 – ≤ 10.11.22 11.10.0

References