Hi everyone, Here we go again. A third local-root flaw in the Linux kernel has been disclosed today in the same code area as Copy Fail and Dirty Frag. The bug, named "Fragnesia" by researcher William Bowling of the V12 security team, is tracked as CVE-2026-46300, and a working proof-of-concept is already public. Fragnesia is a logic flaw in the core socket-buffer code (skb_try_coalesce loses the SKBFL_SHARED_FRAG marker) that the XFRM ESP-in-TCP receive path then turns into in-place AES-GCM decryption over page-cache pages an unprivileged user controls. The end result is arbitrary byte writes into read-only files such as /usr/bin/su, i.e. immediate local root. All supported AlmaLinux releases (8, 9, 10) are affected through esp4 / esp6, which ship in the standard kernel package. AlmaLinux 9 and 10 are additionally affected through rxrpc, but only on systems that have installed the kernel-modules-partner package from the Devel repository. AlmaLinux 8 does not build rxrpc. The AlmaLinux core team has built patched kernels using the upstream skbuff fix, ahead of any Red Hat update, with ALESCo approval. They are available in the almalinux-testing repository today and will move to production once the community has helped verify them. AlmaLinux 8: kernel-4.18.0-553.124.2.el8_10 AlmaLinux 9: kernel-5.14.0-611.54.4.el9_7 AlmaLinux 10: kernel-6.12.0-124.56.2.el10_1 A dedicated Kitten 10 build will follow shortly. If you run AlmaLinux anywhere untrusted users can get a shell (multi-tenant hosts, container build farms, CI runners, shared developer boxes), please install the patched kernel from testing and help us verify it, or apply the one-line modprobe blacklist mitigation in the blog post. The same mitigation already used for Dirty Frag (esp4 / esp6 / rxrpc) also blocks Fragnesia, so if you applied that one you are already covered. Full write-up, install steps, NVRs, and the mitigation command: https://almalinux.org/blog/2026-05-13-fragnesia-cve-2026-46300/ References: NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-46300 Red Hat: https://access.redhat.com/security/cve/CVE-2026-46300 PoC: https://github.com/v12-security/pocs/tree/main/fragnesia Please report any problems with the patched kernel in https://chat.almalinux.org or on https://bugs.almalinux.org so we can get this into the production repositories quickly. -- Jonathan Wright AlmaLinux OS Foundation Mattermost: chat <https://chat.almalinux.org/almalinux/messages/@jonathan>