Last updated 4 July 2026
Last updated 27 August 2026
A use-after-free vulnerability in the Linux Kernel traffic control index filter (tcindex) can be exploited to achieve local privilege escalation. The tcindexdelete function which does not properly deactivate filters in case of a perfect hashes while deleting the underlying structure which can later lead to double freeing the structure. A local attacker user can use this vulnerability to elevate its privileges to root.
We recommend upgrading past commit 8c710f75256bb3cf05ac7b1672c82b92c43f3d28 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/ .
End of life: 6/1/2011, End of support: 6/1/2011, Latest version: 6.06.2
End of life: 6/1/2011, End of support: 6/1/2011, Latest version: 6.06.2
End of life: 4/30/2006, End of support: 10/26/2004, Latest version: 4.10
End of life: 4/30/2006, End of support: 10/26/2004, Latest version: 4.10
End of life: 4/13/2007, End of support: 4/13/2007, Latest version: 5.10
End of life: 4/13/2007, End of support: 4/13/2007, Latest version: 5.10
End of life: 6/1/2027, End of support: 9/30/2024, Latest version: 22.04.5
End of life: 6/1/2027, End of support: 9/30/2024, Latest version: 22.04.5
End of life: 5/31/2029, End of support: 5/31/2029, Latest version: 24.04.4
End of life: 5/31/2029, End of support: 5/31/2029, Latest version: 24.04.4
End of life: 5/29/2031, End of support: 5/29/2031, Latest version: 26.04.1
Hello, Everyone
I wanted to represent, That we confirmed the ubuntu and canonical websites are back up and working, that is exciting
relunsec@relunsec:~$ ping ubuntu.com PING ubuntu.com (185.125.190.29) 56(84) bytes of data. 64 bytes from website-content-cache-3.ps5.canonical.com (185.125.190.29): icmpseq=1 ttl=53 time=44.4 ms 64 bytes from website-content-cache-3.ps5.canonical.com (185.125.190.29): icmpseq=2 ttl=53 time=43.0 ms 64 bytes from website-content-cache-3.ps5.canonical.com (185.125.190.29): icmpseq=3 ttl=53 time=44.1 ms ^C --- ubuntu.com ping statistics --- 3 packets transmitted, 3 received, 0% packet loss, time 2003ms rtt min/avg/max/mdev = 43.030/43.845/44.375/0.585 ms relunsec@relunsec:~$ sudo apt update [sudo: authenticate] Password: Hit:1 http://ma.archive.ubuntu.com/ubuntu resolute InRelease Hit:2 http://ma.archive.ubuntu.com/ubuntu resolute-updates InRelease Hit:3 http://security.ubuntu.com/ubuntu resolute-security InRelease Hit:4 http://ma.archive.ubuntu.com/ubuntu resolute-backports InRelease All packages are up to date. relunsec@relunsec:~$ ping snapcraft.io PING snapcraft.io (185.125.190.20) 56(84) bytes of data. 64 bytes from website-content-cache-1.ps5.canonical.com (185.125.190.20): icmpseq=1 ttl=50 time=47.3 ms 64 bytes from website-content-cache-1.ps5.canonical.com (185.125.190.20): icmpseq=2 ttl=50 time=49.4 ms ^C --- snapcraft.io ping statistics --- 2 packets transmitted, 2 received, 0% packet loss, time 1001ms rtt min/avg/max/mdev = 47.253/48.332/49.412/1.079 ms relunsec@relunsec:~$ ping security.ubuntu.com PING security.ubuntu.com (91.189.91.82) 56(84) bytes of data. 64 bytes from ubuntu-mirror-2.ps6.canonical.com (91.189.91.82): icmpseq=1 ttl=47 time=203 ms 64 bytes from ubuntu-mirror-2.ps6.canonical.com (91.189.91.82): icmpseq=2 ttl=47 time=225 ms 64 bytes from ubuntu-mirror-2.ps6.canonical.com (91.189.91.82): icmpseq=3 ttl=47 time=145 ms ^C --- security.ubuntu.com ping statistics --- 3 packets transmitted, 3 received, 0% packet loss, time 2003ms rtt min/avg/max/mdev = 145.119/191.014/225.377/33.764 ms relunsec@relunsec:~$ nslookup ubuntu.com Server: 127.0.0.53 Address: 127.0.0.53#53
Non-authoritative answer: Name: ubuntu.com Address: 185.125.190.29 Name: ubuntu.com Address: 185.125.190.21 Name: ubuntu.com Address: 185.125.190.20 Name: ubuntu.com Address: 2620:2d:4000:1::28 Name: ubuntu.com Address: 2620:2d:4000:1::26 Name: ubuntu.com Address: 2620:2d:4000:1::27
relunsec@relunsec:~$ ping canonical.com PING canonical.com (185.125.190.29) 56(84) bytes of data. 64 bytes from website-content-cache-3.ps5.canonical.com (185.125.190.29): icmpseq=1 ttl=53 time=44.0 ms 64 bytes from website-content-cache-3.ps5.canonical.com (185.125.190.29): icmpseq=2 ttl=53 time=43.2 ms 64 bytes from website-content-cache-3.ps5.canonical.com (185.125.190.29): icmpseq=3 ttl=53 time=44.9 ms ^C --- canonical.com ping statistics --- 3 packets transmitted, 3 received, 0% packet loss, time 2003ms rtt min/avg/max/mdev = 43.181/44.051/44.946/0.720 ms relunsec@relunsec:~$
Everything working no slowdown, no connection timedout, no connection refused, That is a good news, Now peoples must update and upgrade their system now and your snaps and monitor the status of CopyFail, before attackers resume their operation.
Best Regards, RelunSec
This new Linux kernel bug called Copy Fail (CVE-2026-31431) is kinda terrifying because it’s not complicated at all. A normal user can run a tiny 732-byte script and get root, no race conditions or luck required, and it works across major distros like Ubuntu, RHEL, and SUSE. The exploit quietly modifies the page cache instead of the file on disk, so integrity checks don’t catch it, but the kernel still executes the tampered version in memory.
Even worse, since the page cache is shared, it can potentially cross container boundaries too. Patch ASAP if your distro hasn’t already, because this one feels way too reliable…