CVE-2024-44991

Warning splats via concurrent TCP namespace cleanup

Published Sep 4, 2024 · Updated May 11, 2026

Race condition in the Linux kernel allows local users to trigger erroneous TCP refcount warnings during failed network namespace creation. Concurrent tcp_sk_exit_batch() calls let tcp_twsk_purge() remove TIME-WAIT sockets from any dying namespace, so both cleanup paths decrement an unexpected tw_refcount. The trigger requires local network namespace creation and a clone failure; the upstream report identifies warning splats but no socket loss or use-after-free.

CVSS severity5.5
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in the Linux kernel allows local users to trigger erroneous TCP refcount warnings during failed network namespace creation. Concurrent tcp_sk_exit_batch() calls let tcp_twsk_purge() remove TIME-WAIT sockets from any dying namespace, so both cleanup paths decrement an unexpected tw_refcount. The trigger requires local network namespace creation and a clone failure; the upstream report identifies warning splats but no socket loss or use-after-free.

The record

CVE
CVE-2024-44991
Published
Sep 4, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 4, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=6.1
  2. Affected versionversion=e9bd0cca09d13ac2f08d25e195203e42d4ad1ce8 <565d121b69980637f040eb4d84289869cdaabedf
  3. Affected versionversion=e9bd0cca09d13ac2f08d25e195203e42d4ad1ce8 <99580ae890ec8bd98b21a2a9c6668f8f1555b62e
  4. Affected versionversion=e9bd0cca09d13ac2f08d25e195203e42d4ad1ce8 <e3d9de3742f4d5c47ae35f888d3023a5b54fcd2f
  5. Affected versionversion=e9bd0cca09d13ac2f08d25e195203e42d4ad1ce8 <f6fd2dbf584a4047ba88d1369ff91c9851261ec1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.1; version=e9bd0cca09d13ac2f08d25e195203e42d4ad1ce8 <565d121b69980637f040eb4d84289869cdaabedf; version=e9bd0cca09d13ac2f08d25e195203e42d4ad1ce8 <99580ae890ec8bd98b21a2a9c6668f8f1555b62e; version=e9bd0cca09d13ac2f08d25e195203e42d4ad1ce8 <e3d9de3742f4d5c47ae35f888d3023a5b54fcd2f; version=e9bd0cca09d13ac2f08d25e195203e42d4ad1ce8 <f6fd2dbf584a4047ba88d1369ff91c9851261ec1

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5CanonicalCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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