CVE-2026-102560: libsoup: libsoup: Heap buffer overflow during outgoing permessage-deflate buffer growth

Severity: Critical

CVSS Score: 9.8

A flaw was found in libsoup. When the permessage-deflate WebSocket extension compresses a very large outgoing message, truncated size calculations used for GByteArray growth could wrap, causing zlib to write past the allocated buffer and resulting in a heap buffer overflow.