CVE-2026-98490
Received Received - Intake

Use-After-Free in Linux Kernel Open vSwitch Conntrack

Publication date: 2026-10-18

Last updated on: 2026-10-18

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: conntrack: fix helper UAF due to extensions realloc While calling the helpers, a raw pointer to the extensions area is wired into expectations list: -> nf_ct_helper() -> helper->help() -> nf_ct_expect_related_report() -> nf_ct_expect_insert() -> hlist_add_head_rcu(&exp->lnode, &master_help->expectations) In case the connection is not confirmed yet, more extensions can be added afterwards with *_ext_add() calls reallocating the extension space and leaving the now invalid pointer in the expectations list that is later accessed while removing the expectation. Make sure that helpers are called at the end after all the other extensions are already added. Note that the helper rejection now leaves the mark and labels set, but that's not different from how the NAT was handled before or how the mark and the labels were handled on confirmation failure. And there are no atomicity guarantees provided by the API anyway.

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Meta Information

Published
2026-10-18
Last Modified
2026-10-18
Generated
2026-10-18
AI Q&A
2026-10-18
EPSS Evaluated
N/A
NVD
CVE-2026-98490
EUVD
EUVD-2026-103730

Affected Vendors & Products

Showing 5 associated CPEs
Vendor Product Version / Range
Linux Linux cae3a2627520c3795b54533c5328b77af3405dbe
Linux Linux cae3a2627520c3795b54533c5328b77af3405dbe
Linux Linux cae3a2627520c3795b54533c5328b77af3405dbe
Linux Linux cae3a2627520c3795b54533c5328b77af3405dbe
Linux Linux 4.3

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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 use-after-free (UAF) issue in the Open vSwitch connection tracking system. When helpers are called, a raw pointer to the extensions area is stored in the expectations list. If more extensions are added later, the extension space may be reallocated, leaving an invalid pointer in the list. This invalid pointer is later accessed when removing the expectation, causing a UAF condition.

Impact Analysis

This vulnerability could allow an attacker to cause a denial-of-service (DoS) condition or potentially execute arbitrary code in the kernel. It may lead to system crashes, data corruption, or unauthorized access if exploited.

Mitigation Strategies

Update the Linux kernel to the latest patched version to resolve the use-after-free issue in Open vSwitch connection tracking. Monitor for unusual network activity or crashes that may indicate exploitation.

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