Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-06-24T00:00:00 kernel: sctp: fix OOB write to userspace in sctp_getsockopt_peer_auth_chunks 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CWE-131

In the Linux kernel, the following vulnerability has been resolved: sctp: fix OOB write to userspace in sctp_getsockopt_peer_auth_chunks sctp_getsockopt_peer_auth_chunks() checks that the caller's optval buffer is large enough for the peer AUTH chunk list with if (len < num_chunks) return -EINVAL; but then writes num_chunks bytes to p->gauth_chunks, which lives at offset offsetof(struct sctp_authchunks, gauth_chunks) == 8 inside optval. The check is missing the sizeof(struct sctp_authchunks) = 8-byte header. When the caller supplies len == num_chunks (for any num_chunks > 0) the test passes but copy_to_user() writes sizeof(struct sctp_authchunks) = 8 bytes past the declared buffer. The sibling function sctp_getsockopt_local_auth_chunks() at the next line already has the correct check: if (len < sizeof(struct sctp_authchunks) + num_chunks) return -EINVAL; Align the peer variant with its sibling. Reproducer confirms on v7.0-13-generic: an unprivileged userspace caller that opens a loopback SCTP association with AUTH enabled, queries num_chunks with a short optval, then issues the real getsockopt with len == num_chunks and sentinel bytes painted past the buffer observes those sentinel bytes overwritten with the peer's AUTH chunk type. The bytes written are under the peer's control but land in the caller's own userspace; this is not a kernel memory corruption, but it is a kernel-side contract violation that can silently corrupt adjacent userspace data.

A flaw was found in the Linux kernel's Stream Control Transmission Protocol (SCTP) implementation. An unprivileged local user could exploit an out-of-bounds write vulnerability in the `sctp_getsockopt_peer_auth_chunks` function. This occurs due to an incorrect size check, allowing the kernel to write past the intended buffer in userspace. This flaw can lead to the silent corruption of adjacent userspace data, impacting data integrity.

Red Hat Enterprise Linux 10 Fix deferred kernel Red Hat Enterprise Linux 6 Out of support scope kernel Red Hat Enterprise Linux 7 Fix deferred kernel Red Hat Enterprise Linux 7 Fix deferred kernel-rt Red Hat Enterprise Linux 8 Fix deferred kernel Red Hat Enterprise Linux 8 Fix deferred kernel-rt Red Hat Enterprise Linux 9 Fix deferred kernel Red Hat Enterprise Linux 9 Fix deferred kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-53004 https://nvd.nist.gov/vuln/detail/CVE-2026-53004 https://lore.kernel.org/linux-cve-announce/2026062448-CVE-2026-53004-09a9@gregkh/T