Linux Kernel up to 7.0.9 sctp sctp_getsockopt_peer_auth_chunks gauth_chunks out-of-bounds write

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.0.9. It has been rated as critical. This affects the function sctp_getsockopt_peer_auth_chunks of the component sctp. Performing a manipulation of the argument gauth_chunks results in out-of-bounds write. This vulnerability is known as CVE-2026-53004. Access to the local network is required for this attack. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 7.0.9. This affects the function sctp_getsockopt_peer_auth_chunks of the component sctp. The manipulation of the argument gauth_chunks with an unknown input leads to a out-of-bounds write vulnerability. CWE is classifying the issue as CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-53004 since 06/09/2026. The exploitability is told to be easy. The attack needs to approached within the local network. Technical details are known, but no exploit is available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 06/24/2026).

Upgrading to version 5.10.258, 5.15.209, 6.1.175, 6.6.141, 6.12.91, 6.18.33 or 7.0.10 eliminates this vulnerability. Applying the patch a132e199de69e2a45628aa8534df1bf5d44e1b6e/2b5a2c957c7769d40110f725cf23987fcef50d75/d45c7e99caf915b0f6c716bd8ffe9d45b9685761/d67fbc6dea5dbf7f46c618ebf65910a276078e20/6849b995cda88a677bf08a05765d1db7905974fc/70a089cc9590aa347a61e84434116ab74619e3c3/6bcf8fe4ef7967b22b814cbae9a57bbd3c853410/0cf004ffb61cd32d140531c3a84afe975f9fc7ea is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.10.257
• 5.15.208
• 6.1.174
• 6.6.140
• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
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• 6.12.9
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• 6.12.84
• 6.12.85
• 6.12.86
• 6.12.87
• 6.12.88
• 6.12.89
• 6.12.90
• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
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• 6.18.13
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• 6.18.15
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• 6.18.20
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• 6.18.25
• 6.18.26
• 6.18.27
• 6.18.28
• 6.18.29
• 6.18.30
• 6.18.31
• 6.18.32
• 7.0.0
• 7.0.1
• 7.0.2
• 7.0.3
• 7.0.4
• 7.0.5
• 7.0.6
• 7.0.7
• 7.0.8
• 7.0.9

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Entryinfo

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