CVE-2026-98548 Linux Kernel SCTP Use-After-Free

CVE-2026-98548 is a use-after-free flaw in the Linux kernel SCTP subsystem that allows a malicious SCTP peer (or unprivileged local user) to corrupt kernel memory. When an SCTP association is in COOKIE-ECHOED state and receives a bundled ERROR(Stale Cookie)[DATA] packet, kernel processing of the ERROR chunk triggers transport removal while maintaining dangling references in association fields. Subsequently, DATA chunk or FWD-TSN dereference the freed memory, causing corruption.

Declared CVSS is 9.8 (critical). The vulnerability was disclosed 2026-10-18 with proposed patch. Technical validation exists via KASAN report and stack traces in NVD description demonstrating the use-after-free. Public discussion on X (2026-11-03) confirms community awareness. No confirmed public exploit in available data, but criticality and trigger simplicity (any unprivileged SCTP peer) make it urgent.

Apply kernel security updates immediately from your Linux distributor. If you use SCTP, verify kernel version and apply resolution patches. Where possible, restrict SCTP traffic to trusted hosts and disable the protocol if not required. Monitor kernel logs for KASAN signals or memory corruption indicators. Review update procedures to ensure critical kernel patches are deployed within 7 days of publication.