CVE-2026-31631Network attack vector

Pre-auth disclosure and crash via RXGK overread

Published Apr 24, 2026 · Updated Apr 24, 2026

Out-of-bounds read in RXGK authentication in Linux Kernel allows remote attackers to obtain indirect kernel-memory disclosure or crash the system. rxgk_do_verify_authenticator() compares the 20-byte connection nonce before confirming that the decrypted authenticator buffer contains those bytes. Reachability requires an RXGK-capable AF_RXRPC service and supported encryption type; a crafted short response is processed before authentication completes.

CVSS severity8.2
High
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in RXGK authentication in Linux Kernel allows remote attackers to obtain indirect kernel-memory disclosure or crash the system. rxgk_do_verify_authenticator() compares the 20-byte connection nonce before confirming that the decrypted authenticator buffer contains those bytes. Reachability requires an RXGK-capable AF_RXRPC service and supported encryption type; a crafted short response is processed before authentication completes.

The record

CVE
CVE-2026-31631
Published
Apr 24, 2026
Updated
Apr 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=6.16
  2. Affected versionversion=9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a <1c4422d8be81718ecb15d79aedff607323085201
  3. Affected versionversion=9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a <794586789800b16dcbe235452494f4223ac80413
  4. Affected versionversion=9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a <f564af387c8c28238f8ebc13314c589d7ba8475d

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.16; version=9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a <1c4422d8be81718ecb15d79aedff607323085201; version=9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a <794586789800b16dcbe235452494f4223ac80413; version=9d1d2b59341f58126a69b51f9f5f8ccb9f12e54a <f564af387c8c28238f8ebc13314c589d7ba8475d

Published CVSS scores

8.2LinuxCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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