Critical 9.8Published Apr 24, 2026

CVE-2026-31637rxrpc: reject undecryptable rxkad response tickets

Updated under an hour ago (Oct 27, 2026, 10:10 PM ET)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

In the Linux kernel, the following vulnerability has been resolved: rxrpc: reject undecryptable rxkad response tickets rxkad_decrypt_ticket() decrypts the RXKAD response ticket and then parses the buffer as plaintext without checking whether crypto_skcipher_decrypt() succeeded. A malformed RESPONSE can therefore use a non-block-aligned ticket length, make the decrypt operation fail, and still drive the ticket parser with attacker-controlled bytes. Check the decrypt result and abort the connection with RXKADBADTICKET when ticket decryption fails.

CVSS: 9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-754
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 17926a79320afa9b95df6b977b40cca6d8713cea before 252157d939d179b5d767cb860ff8fa7f8723b67a; from 17926a79320afa9b95df6b977b40cca6d8713cea before a75b3b361dd481d942c5f259a82d59718a41092c; from 17926a79320afa9b95df6b977b40cca6d8713cea before b3a808cd0790b5075aaa2bc3588edf02cd71d352; from 17926a79320afa9b95df6b977b40cca6d8713cea before 47073aab8a3a5a7b41c9bd37d2a3dcbeeccd6c8a; from 17926a79320afa9b95df6b977b40cca6d8713cea before a149dcae23309df9de1c3b6b5d468610ef5ab7de; 17926a79320afa9b95df6b977b40cca6d8713cea builds before 22f6258e7b31dba9bf88dce4e3ee7f0f20072e60; 17926a79320afa9b95df6b977b40cca6d8713cea builds before 58fcd1b156152613ba00a064a129fb69507ddd7d; from 17926a79320afa9b95df6b977b40cca6d8713cea before fe4447cd95623b1cfacc15f280aab73a6d7340b2	CNA record
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem siemens:simatic_s7_1500_tm_mfp_gnu_linux_subsystem (from the name)	all versions	CISA ADP
linux linux_kernel linux:linux_kernel	from 2.6.22.1 before 6.6.135; from 6.7 before 6.12.82; from 6.13 before 6.18.23; from 6.19 before 6.19.13; 2.6.22; 7.0; 7.0; 7.0; and 4 more ranges	NVD

References

References

https://git.kernel.org/stable/c/252157d939d179b5d767cb860ff8fa7f8723b67a
https://git.kernel.org/stable/c/a75b3b361dd481d942c5f259a82d59718a41092c
https://git.kernel.org/stable/c/b3a808cd0790b5075aaa2bc3588edf02cd71d352
https://git.kernel.org/stable/c/47073aab8a3a5a7b41c9bd37d2a3dcbeeccd6c8a	patch
https://git.kernel.org/stable/c/a149dcae23309df9de1c3b6b5d468610ef5ab7de	patch
https://git.kernel.org/stable/c/22f6258e7b31dba9bf88dce4e3ee7f0f20072e60	patch
https://git.kernel.org/stable/c/58fcd1b156152613ba00a064a129fb69507ddd7d	patch
https://git.kernel.org/stable/c/fe4447cd95623b1cfacc15f280aab73a6d7340b2	patch
https://cert-portal.siemens.com/productcert/html/ssa-784472.html

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.