CVE-2026-23139
Unknown Unknown - Not Provided
Denial of Service via Memory Leak in Linux netfilter nf_conncount

Publication date: 2026-02-14

Last updated on: 2026-04-03

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conncount: update last_gc only when GC has been performed Currently last_gc is being updated everytime a new connection is tracked, that means that it is updated even if a GC wasn't performed. With a sufficiently high packet rate, it is possible to always bypass the GC, causing the list to grow infinitely. Update the last_gc value only when a GC has been actually performed.
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Meta Information
Published
2026-02-14
Last Modified
2026-04-03
Generated
2026-06-16
AI Q&A
2026-02-14
EPSS Evaluated
2026-06-15
NVD
CVE-2026-23139
EUVD
EUVD-2026-5898
Affected Vendors & Products
Showing 8 associated CPEs
Vendor Product Version / Range
linux linux_kernel 6.19
linux linux_kernel 6.19
linux linux_kernel 6.19
linux linux_kernel 6.19
linux linux_kernel From 6.13 (inc) to 6.18.6 (exc)
linux linux_kernel From 6.2 (inc) to 6.6.121 (exc)
linux linux_kernel From 6.7 (inc) to 6.12.66 (exc)
linux linux_kernel From 5.19 (inc) to 6.1.161 (exc)
Helpful Resources
Exploitability
CWE
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability exists in the Linux kernel's netfilter component, specifically in the nf_conncount module. The issue is that the variable last_gc, which tracks the last garbage collection (GC) time, is updated every time a new network connection is tracked, regardless of whether a GC was actually performed.

Because last_gc is updated even without performing GC, an attacker can send packets at a high rate to continuously bypass the garbage collection process. This causes the internal list that tracks connections to grow without limit, potentially leading to resource exhaustion.

The fix involves updating last_gc only when a garbage collection has actually been performed, preventing the list from growing infinitely.

Impact Analysis

This vulnerability can lead to resource exhaustion in the Linux kernel's netfilter subsystem by allowing the connection tracking list to grow infinitely.

An attacker could exploit this by sending a high rate of packets, causing the system to consume excessive memory or processing resources, potentially leading to degraded performance or denial of service.

Compliance Impact

I don't know

Detection Guidance

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