CVE-2026-5132

Mattermost versions 11.9.x ≤ 11.9.0, 11.8.x ≤ 11.8.4, 11.7.x ≤ 11.7.7, and 10.11.x ≤ 10.11.22 fail to limit the size of unpacked SDP messages compressed with zlib in Calls WebSocket messages. An authenticated attacker (low privileges) can send many SDP messages that decompress to a large size, ca...

CVE-2026-5132 Unbounded zlib decompression in Calls SDP WebSocket messages

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:...