CVE-2026-98491

About vulnerability

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.

Affected product:

AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , CloudLinux 7 ELS , Debian 10 ELS , Debian 11 ELS , Oracle Linux 7 ELS , RHEL 7 ELS , TuxCare 9.6 ESU , TuxCare 9.8 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS

Affected packages:

kernel @ 5.10.0 (+18 more)

Live-patch status from KernelCare for each operating system.