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CVE-2026-98491

Linux: net: openvswitch: conntrack: avoid modifying shared unconfirmed ct entry

Linux LinuxOperating systems
Open in ThreatlineRecord JSON
CVSS
NoneNot scored
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.21%Chance of exploitation activity in the next 30 days, higher than 10% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in37e3c878b183a115f9a114067f9ef3b408ad27fbAlso 707c2dc77891a874f4e8c52c285a511079164ec8, 55e5256adf3940e71802e2f749cacf81518726b0 and 2 moreCVE List
Published18 Oct 2026Updated 19 Oct 2026CVE List

What fixes it

  • 37e3c878b183a115f9a114067f9ef3b408ad27fbLinuxCVE List
  • 707c2dc77891a874f4e8c52c285a511079164ec8LinuxCVE List
  • 55e5256adf3940e71802e2f749cacf81518726b0LinuxCVE List
  • 457e0df1b5711fbeb7ba1b6bfd826f5ef30e7e55LinuxCVE List
  • 26b2bd70d22457556e2fa01cbf1192cb1a94d619LinuxCVE List

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

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.

  1. Then it looses the confirmation keeping the entry unconfirmed.
  2. 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.

Text from CVE List

Affected versions 18

  • Linuxaffected: cae3a2627520c3795b54533c5328b77af3405dbe before e0fa5ea434b7e8467ef3adc64e3858b1ca2a642dCVE List
  • Linuxaffected: cae3a2627520c3795b54533c5328b77af3405dbe before 37e3c878b183a115f9a114067f9ef3b408ad27fbCVE List
  • Linuxaffected: cae3a2627520c3795b54533c5328b77af3405dbe before 707c2dc77891a874f4e8c52c285a511079164ec8CVE List
  • Linuxaffected: cae3a2627520c3795b54533c5328b77af3405dbe before de41ee24f77b0fc45397db3e277cae2adbd43dfeCVE List
  • Linuxaffected: cae3a2627520c3795b54533c5328b77af3405dbe before 55e5256adf3940e71802e2f749cacf81518726b0CVE List
  • Linuxaffected: cae3a2627520c3795b54533c5328b77af3405dbe before e2829ae5459ddb5fce526b2e84697edf6c0c3cefCVE List
  • Linuxaffected: cae3a2627520c3795b54533c5328b77af3405dbe before 457e0df1b5711fbeb7ba1b6bfd826f5ef30e7e55CVE List
  • Linuxaffected: cae3a2627520c3795b54533c5328b77af3405dbe before 26b2bd70d22457556e2fa01cbf1192cb1a94d619CVE List
  • Linuxaffected: 4.3CVE List
  • Linuxunaffected: all versions before 4.3CVE List
  • Linuxunaffected: 5.10.271 through 5.10.*CVE List
  • Linuxunaffected: 5.15.222 through 5.15.*CVE List
  • Linuxunaffected: 6.1.189 through 6.1.*CVE List
  • Linuxunaffected: 6.6.158 through 6.6.*CVE List
  • Linuxunaffected: 6.12.112 through 6.12.*CVE List
  • Linuxunaffected: 6.18.55 through 6.18.*CVE List
  • Linuxunaffected: 7.2.9 through 7.2.*CVE List
  • Linuxunaffected: 7.3CVE List

References 8