CVE-2026-53004: Linux kernel · sctp: fix OOB write to userspace in sctp_getsockopt_peer_auth_chunks
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in d67fbc6dea5dbf7f46c618ebf65910a276078e20 : update Linux kernel when convenient.
Data as of 6 Nov 2026, 16:49 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
Thin evidence
One scorer or none- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-11-06.
- Patch
- Available – fixed in d67fbc6dea5dbf7f46c618ebf65910a276078e20, d45c7e99caf915b0f6c716bd8ffe9d45b9685761, a132e199de69e2a45628aa8534df1bf5d44e1b6e +5
Exploitation evidence
Disclosed: evidence found.
CVE published 24 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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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.
References
- git.kernel.org/stable/c/a132e199de69e2a45628aa8534df1bf5d44e1b6e (opens in a new tab)
- git.kernel.org/stable/c/2b5a2c957c7769d40110f725cf23987fcef50d75 (opens in a new tab)
- git.kernel.org/stable/c/d45c7e99caf915b0f6c716bd8ffe9d45b9685761 (opens in a new tab)
- git.kernel.org/stable/c/d67fbc6dea5dbf7f46c618ebf65910a276078e20 (opens in a new tab)
- git.kernel.org/stable/c/6849b995cda88a677bf08a05765d1db7905974fc (opens in a new tab)
- git.kernel.org/stable/c/70a089cc9590aa347a61e84434116ab74619e3c3 (opens in a new tab)
- git.kernel.org/stable/c/6bcf8fe4ef7967b22b814cbae9a57bbd3c853410 (opens in a new tab)
- git.kernel.org/stable/c/0cf004ffb61cd32d140531c3a84afe975f9fc7ea (opens in a new tab)