CVE-2026-31640Network attack vector

Service interruption via unreleased RxRPC response packets

Published Apr 24, 2026 · Updated Apr 24, 2026

Incorrect RxRPC response handling in affected Linux kernel releases allows remote attackers to interrupt service via network traffic. The rxrpc_post_response() function reads the incoming packet's private challenge serial instead of the cached response's serial, so the comparison never selects the newer response and an unused packet remains unreleased. Network reachability to an active RxRPC endpoint is required; repeated triggering consumes kernel memory without reading or changing data.

CVSS severity7.5
High
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect RxRPC response handling in affected Linux kernel releases allows remote attackers to interrupt service via network traffic. The rxrpc_post_response() function reads the incoming packet's private challenge serial instead of the cached response's serial, so the comparison never selects the newer response and an unused packet remains unreleased. Network reachability to an active RxRPC endpoint is required; repeated triggering consumes kernel memory without reading or changing data.

The record

CVE
CVE-2026-31640
Published
Apr 24, 2026
Updated
Apr 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-401, T1499
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=5800b1cf3fd8ccab752a101865be1e76dac33142 <20386e7f8d97475b8d815873e246423317ec4260
  2. Affected versionversion=5800b1cf3fd8ccab752a101865be1e76dac33142 <9132b1a7bf83b4a8042fffbc99d075b727a16742
  3. Affected versionversion=5800b1cf3fd8ccab752a101865be1e76dac33142 <b33f5741bb187db8ff32e8f5b96def77cc94dfca
  4. Affected versionversion=6.16

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5800b1cf3fd8ccab752a101865be1e76dac33142 <20386e7f8d97475b8d815873e246423317ec4260; version=5800b1cf3fd8ccab752a101865be1e76dac33142 <9132b1a7bf83b4a8042fffbc99d075b727a16742; version=5800b1cf3fd8ccab752a101865be1e76dac33142 <b33f5741bb187db8ff32e8f5b96def77cc94dfca; version=6.16

Published CVSS scores

7.5kernel.orgCVSS: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

CWE-401Missing Release of Memory after Effective Lifetime
T1499Endpoint Denial of Service

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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