In the Linux kernel, the following vulnerability has been resolved:

net/sched: act_mirred: don't override retval if we already lost the skb

If we're redirecting the skb, and haven't called tcf_mirred_forward(),
yet, we need to tell the core to drop the skb by setting the retcode
to SHOT. If we have called tcf_mirred_forward(), however, the skb
is out of our hands and returning SHOT will lead to UaF.

Move the retval override to the error path which actually need it.

References

• https://nvd.nist.gov/vuln/detail/CVE-2024-26739
• https://git.kernel.org/stable/c/166c2c8a6a4dc2e4ceba9e10cfe81c3e469e3210
• https://git.kernel.org/stable/c/28cdbbd38a4413b8eff53399b3f872fd4e80db9d
• https://git.kernel.org/stable/c/f4e294bbdca8ac8757db436fc82214f3882fc7e7