CVE-2026-64551
CriticalCVSS 9.1Exploitation Probability (EPSS)
Low risk41th percentile - higher than 41% of all known CVEs
Summary
In the Linux kernel, SCTP's handling of STALE_COOKIE error in COOKIE_ECHOED state reads the staleness field from the first error cause instead of the STALE_COOKIE cause, leading to out-of-bounds read and uninitialized memory leak.
Risk Assessment
The organization may be exposed to kernel uninitialized memory leak to a remote peer via SCTP, potentially disclosing sensitive data. The attack is reachable by an unprivileged process using a raw SCTP socket.
Recommendation
Apply the Linux kernel patch that checks the STALE_COOKIE cause length before reading and passes the correct cause to the handler.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: sctp: validate STALE_COOKIE cause length before reading staleness When an ERROR chunk with a STALE_COOKIE cause is received in the COOKIE_ECHOED state, sctp_sf_do_5_2_6_stale() reads the 4-byte Measure of Staleness that follows the cause header: err = (struct sctp_errhdr *)(chunk->skb->data); stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err))); err is the first cause in the chunk, not the STALE_COOKIE cause that caused the dispatch, and nothing guarantees the staleness field is present. sctp_walk_errors() only requires a cause to be as long as the 4-byte header, so for a STALE_COOKIE cause of length 4 the read runs past the cause, and for a minimal ERROR chunk past skb->tail. The value is echoed to the peer in the Cookie Preservative of the reply INIT, leaking uninitialized memory. sctp_sf_cookie_echoed_err() already walks to the STALE_COOKIE cause, so check its length there and pass it to sctp_sf_do_5_2_6_stale(), which reads that cause instead of the first one. A STALE_COOKIE cause too short to hold the staleness field is discarded. The read is reachable by any peer that can drive an association into COOKIE_ECHOED, including an unprivileged process using a raw SCTP socket in a user and network namespace.