Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-07-27T00:00:00 kernel: sctp: validate STALE_COOKIE cause length before reading staleness 7.0 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

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.

A flaw was found in the Linux kernel's Stream Control Transmission Protocol (SCTP). This vulnerability allows a remote attacker or a local unprivileged user to potentially access and disclose sensitive information. By sending a malformed error message, the system can be tricked into reading and then leaking uninitialized memory, which is then sent back to the attacker.

Red Hat Enterprise Linux 10 Affected kernel Red Hat Enterprise Linux 6 Affected kernel Red Hat Enterprise Linux 7 Affected kernel Red Hat Enterprise Linux 7 Affected kernel-rt Red Hat Enterprise Linux 8 Affected kernel Red Hat Enterprise Linux 8 Affected kernel-rt Red Hat Enterprise Linux 9 Affected kernel Red Hat Enterprise Linux 9 Affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-64551 https://nvd.nist.gov/vuln/detail/CVE-2026-64551 https://lore.kernel.org/linux-cve-announce/2026072737-CVE-2026-64551-1deb@gregkh/T