CVE-2026-80636
Received Received - Intake

Revert ct extension genid infrastructure in Linux kernel

Publication date: 2026-08-28

Last updated on: 2026-08-28

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: conntrack: revert ct extension genid infrastructure This infrastructure is not used anymore after moving ct timeout and helper to use datapath refcount to track object use. Revert commit c56716c69ce1 ("netfilter: extensions: introduce extension genid count") this patch disables all ct extensions (leading to NULL) for unconfirmed conntracks, when this is only targeted at ct helper and ct timeout. There is also codebase that dereferences the ct extension without checking for NULL which could lead to crash.

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Meta Information

Published
2026-08-28
Last Modified
2026-08-28
Generated
2026-09-18
AI Q&A
2026-08-28
EPSS Evaluated
2026-09-15
NVD
CVE-2026-80636
EUVD
EUVD-2026-67512

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a flaw in the connection tracking (conntrack) system. The issue stems from reverting the connection tracking extension generation ID infrastructure, which is no longer used after changes to timeout and helper tracking. This revert disables all connection tracking extensions for unconfirmed connections, leading to potential NULL dereferences in code that does not check for NULL values, which could cause system crashes.

Detection Guidance

This vulnerability affects the Linux kernel's netfilter connection tracking system. Detection requires checking kernel logs for crashes or unexpected behavior related to conntrack extensions. Monitor for NULL pointer dereference errors in kernel logs using dmesg or journalctl commands.

Impact Analysis

This vulnerability could cause system crashes if code dereferences a NULL connection tracking extension without proper checks. This may lead to denial-of-service conditions, disrupting network services or applications relying on the Linux kernel's networking stack.

Compliance Impact

This vulnerability affects compliance with standards and regulations like GDPR and HIPAA by potentially causing system crashes due to dereferencing NULL ct extensions in unconfirmed conntracks. This could lead to data processing interruptions or corruption, impacting data integrity and availability requirements under these regulations.

Mitigation Strategies

Apply the latest kernel security patches from your Linux distribution. If patches are unavailable, disable unused conntrack extensions or consider disabling conntrack helper and timeout features temporarily until patched. Reboot the system after applying updates.

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