CVE-2026-98491

high

Description

In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: conntrack: avoid modifying shared unconfirmed ct entry In a case where skb with an unconfirmed ct entry gets cloned, we may end up committing both but with different sets of extensions. The series of events: 1. The first clone wants to commit and runs the helpers wiring up the extension pointer into the expectation list. 2. Then it looses the confirmation keeping the entry unconfirmed. 3. Second clone now wants to commit labels and adds the new extension for that breaking the pointer in the expectation list causing UAF on the destruction path later. While this is possible to trigger, there should be no practical network pipeline where committing both clones without modifications into the same zone is needed. So, let's just reset the entry in case for some reason we got an skb with a shared one during commit. This doesn't affect any known use cases, but avoids any potential problems with sharing and modification of the unconfirmed ct entry. The fixes tag points to the introduction of helpers, since that's the main UAF trigger for the sharing.

References

https://git.kernel.org/stable/c/e2829ae5459ddb5fce526b2e84697edf6c0c3cef

https://git.kernel.org/stable/c/e0fa5ea434b7e8467ef3adc64e3858b1ca2a642d

https://git.kernel.org/stable/c/de41ee24f77b0fc45397db3e277cae2adbd43dfe

https://git.kernel.org/stable/c/707c2dc77891a874f4e8c52c285a511079164ec8

https://git.kernel.org/stable/c/55e5256adf3940e71802e2f749cacf81518726b0

https://git.kernel.org/stable/c/457e0df1b5711fbeb7ba1b6bfd826f5ef30e7e55

https://git.kernel.org/stable/c/37e3c878b183a115f9a114067f9ef3b408ad27fb

https://git.kernel.org/stable/c/26b2bd70d22457556e2fa01cbf1192cb1a94d619

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-103731

Details

Source: Mitre, NVD

Published: 2026-10-18

Updated: 2026-10-19

Risk Information

CVSS v2

Base Score: 5.6

Vector: CVSS2#AV:L/AC:L/Au:N/C:N/I:P/A:C

Severity: Medium

CVSS v3

Base Score: 7.1

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

Severity: High

EPSS

EPSS: 0.0021