CVE-2026-53004
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.13%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.13% probability · 3th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-787
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/0cf004ffb61cd32d140531c3a84afe975f9fc7eaPatch
- https://git.kernel.org/stable/c/2b5a2c957c7769d40110f725cf23987fcef50d75Patch
- https://git.kernel.org/stable/c/6849b995cda88a677bf08a05765d1db7905974fcPatch
- https://git.kernel.org/stable/c/6bcf8fe4ef7967b22b814cbae9a57bbd3c853410Patch
- https://git.kernel.org/stable/c/70a089cc9590aa347a61e84434116ab74619e3c3Patch
- https://git.kernel.org/stable/c/a132e199de69e2a45628aa8534df1bf5d44e1b6ePatch
- https://git.kernel.org/stable/c/d45c7e99caf915b0f6c716bd8ffe9d45b9685761Patch
- https://git.kernel.org/stable/c/d67fbc6dea5dbf7f46c618ebf65910a276078e20Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.