CVE-2026-5132

Mattermost versions 11.9.0 and earlier, 11.8.4 and earlier, 11.7.7 and earlier, and 10.11.22 and earlier are vulnerable due to insufficient limitations on the size of unpacked SDP messages compressed with zlib. An attacker can exploit this vulnerability to send numerous SDP messages that expand to a large size, potentially leading to denial of service or server crashes. Organizations using these Mattermost versions should prioritize patching to mitigate the risk of service disruption.