CVE-2026-23139Network attack vector

Service interruption via deferred nf_conncount garbage collection

Published Feb 14, 2026 · Updated Feb 14, 2026

Resource exhaustion in affected Linux Kernel releases allows remote attackers to interrupt service with a sustained packet flood. The nf_conncount tracking path updates last_gc for every new connection even when no garbage collection runs, so sustained packet creation continually defers collection and lets its list grow without bound. Network reachability and a sufficiently high packet rate are required; the documented consequence is availability loss through memory exhaustion, not data disclosure or modification.

CVSS severity7.5
High
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in affected Linux Kernel releases allows remote attackers to interrupt service with a sustained packet flood. The nf_conncount tracking path updates last_gc for every new connection even when no garbage collection runs, so sustained packet creation continually defers collection and lets its list grow without bound. Network reachability and a sufficiently high packet rate are required; the documented consequence is availability loss through memory exhaustion, not data disclosure or modification.

The record

CVE
CVE-2026-23139
Published
Feb 14, 2026
Updated
Feb 14, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 14, 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=5.19
  2. Affected versionversion=be69850b461e7b491d87a22e33ab76fdd04b725e <c4cde57c8affdcca5bcff53a1047e15d268bdca1
  3. Affected versionversion=d265929930e2ffafc744c0ae05fb70acd53be1ee <26a82dce2beee39c43c109d9647e16f49cb02a35
  4. Affected versionversion=d265929930e2ffafc744c0ae05fb70acd53be1ee <3cd717359e56f82f06cbf8279b47a7d79880c6f3
  5. Affected versionversion=d265929930e2ffafc744c0ae05fb70acd53be1ee <7811ba452402d58628e68faedf38745b3d485e3c
  6. Affected versionversion=d265929930e2ffafc744c0ae05fb70acd53be1ee <8bdafdf4900040a81422056cabe5e00a37bd101a
  7. Affected versionversion=d265929930e2ffafc744c0ae05fb70acd53be1ee <9f45588993d7f115280fc726119ca86fba32a811
  8. Affected versionversion=f106694733c66a48740c25bc4e212e9b2ea364ce <2c7c71113ed6d3e2f3aca4c088f22283016ff34f

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5.19; version=be69850b461e7b491d87a22e33ab76fdd04b725e <c4cde57c8affdcca5bcff53a1047e15d268bdca1; version=d265929930e2ffafc744c0ae05fb70acd53be1ee <26a82dce2beee39c43c109d9647e16f49cb02a35; version=d265929930e2ffafc744c0ae05fb70acd53be1ee <3cd717359e56f82f06cbf8279b47a7d79880c6f3; version=d265929930e2ffafc744c0ae05fb70acd53be1ee <7811ba452402d58628e68faedf38745b3d485e3c; version=d265929930e2ffafc744c0ae05fb70acd53be1ee <8bdafdf4900040a81422056cabe5e00a37bd101a; version=d265929930e2ffafc744c0ae05fb70acd53be1ee <9f45588993d7f115280fc726119ca86fba32a811; version=f106694733c66a48740c25bc4e212e9b2ea364ce <2c7c71113ed6d3e2f3aca4c088f22283016ff34f

Published CVSS scores

7.5LinuxCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.5NISTCVSS: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

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

T1499.003Application Exhaustion Flood

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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