CVE-2026-98491: Linux Vulnerability (CVSS 7.8)

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.

Metrics

CVSS 3.1

7.8/10

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

EPSS Probability

0.21%

10.7th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= cae3a2627520c3795b54533c5328b77af3405dbe, < e0fa5ea434b7e8467ef3adc64e3858b1ca2a642d; >= cae3a2627520c3795b54533c5328b77af3405dbe, < 37e3c878b183a115f9a114067f9ef3b408ad27fb; >= cae3a2627520c3795b54533c5328b77af3405dbe, < 707c2dc77891a874f4e8c52c285a511079164ec8; >= cae3a2627520c3795b54533c5328b77af3405dbe, < de41ee24f77b0fc45397db3e277cae2adbd43dfe; >= cae3a2627520c3795b54533c5328b77af3405dbe, < 55e5256adf3940e71802e2f749cacf81518726b0; >= cae3a2627520c3795b54533c5328b77af3405dbe, < e2829ae5459ddb5fce526b2e84697edf6c0c3cef; >= cae3a2627520c3795b54533c5328b77af3405dbe, < 457e0df1b5711fbeb7ba1b6bfd826f5ef30e7e55; >= cae3a2627520c3795b54533c5328b77af3405dbe, < 26b2bd70d22457556e2fa01cbf1192cb1a94d619
Linux	Linux	4.3

References

Timeline

Published: Oct 18, 2026
Last Modified: Oct 24, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-98491?

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.

How severe is CVE-2026-98491?

CVE-2026-98491 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.

How do I fix CVE-2026-98491?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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