CVE-2026-31637Network attack vector

Remote unspecified impact via unchecked ticket decryption

Published Apr 24, 2026 · Updated Apr 24, 2026

Unchecked decryption handling in Linux Kernel allows remote attackers to trigger unspecified behavior via malformed RXKAD RESPONSE tickets. The rxkad_decrypt_ticket() path ignores crypto_skcipher_decrypt() failure, so a non-block-aligned ticket enters plaintext parsing with attacker-controlled bytes. Reachability requires an RXRPC service using rxkad, and the CNA does not identify the parser's specific post-failure consequence.

CVSS severity9.8
Critical
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unchecked decryption handling in Linux Kernel allows remote attackers to trigger unspecified behavior via malformed RXKAD RESPONSE tickets. The rxkad_decrypt_ticket() path ignores crypto_skcipher_decrypt() failure, so a non-block-aligned ticket enters plaintext parsing with attacker-controlled bytes. Reachability requires an RXRPC service using rxkad, and the CNA does not identify the parser's specific post-failure consequence.

The record

CVE
CVE-2026-31637
Published
Apr 24, 2026
Updated
Apr 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1210
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 24, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=17926a79320afa9b95df6b977b40cca6d8713cea <22f6258e7b31dba9bf88dce4e3ee7f0f20072e60
  2. Affected versionversion=17926a79320afa9b95df6b977b40cca6d8713cea <47073aab8a3a5a7b41c9bd37d2a3dcbeeccd6c8a
  3. Affected versionversion=17926a79320afa9b95df6b977b40cca6d8713cea <58fcd1b156152613ba00a064a129fb69507ddd7d
  4. Affected versionversion=17926a79320afa9b95df6b977b40cca6d8713cea <a149dcae23309df9de1c3b6b5d468610ef5ab7de
  5. Affected versionversion=17926a79320afa9b95df6b977b40cca6d8713cea <fe4447cd95623b1cfacc15f280aab73a6d7340b2
  6. Affected versionversion=2.6.22

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=17926a79320afa9b95df6b977b40cca6d8713cea <22f6258e7b31dba9bf88dce4e3ee7f0f20072e60; version=17926a79320afa9b95df6b977b40cca6d8713cea <47073aab8a3a5a7b41c9bd37d2a3dcbeeccd6c8a; version=17926a79320afa9b95df6b977b40cca6d8713cea <58fcd1b156152613ba00a064a129fb69507ddd7d; version=17926a79320afa9b95df6b977b40cca6d8713cea <a149dcae23309df9de1c3b6b5d468610ef5ab7de; version=17926a79320afa9b95df6b977b40cca6d8713cea <fe4447cd95623b1cfacc15f280aab73a6d7340b2; version=2.6.22

Published CVSS scores

9.8kernel.orgCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5Amazon LinuxCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1210Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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