CVE-2026-89789

NameCVE-2026-89789
DescriptionIn the Linux kernel, the following vulnerability has been resolved: gtp: add synchronize_net() in gtp_newlink() error path to prevent use-after-free gtp_newlink()'s error path frees tid_hash and addr_hash without waiting for an RCU grace period after clearing sk_user_data. A concurrent gtp_encap_recv() in softirq may still hold the gtp_dev pointer obtained via rcu_dereference_sk_user_data() and access the freed memory. BUG: KASAN: slab-use-after-free in gtp0_pdp_find+0x1f6/0x200 (gtp.c:152) Call Trace: <IRQ> gtp0_pdp_find+0x1f6/0x200 gtp_encap_recv+0x527/0x24b0 udp_queue_rcv_one_skb+0x75f/0xc10 Add synchronize_net() before the kfree calls in out_hashtable, which covers all error paths from both gtp_encap_enable() and gtp_create_sockets().
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDSA-6528-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)bookworm6.1.176-1vulnerable
bookworm (security)6.1.187-1vulnerable
trixie6.12.107-1vulnerable
trixie (security)6.12.111-1fixed
forky7.2.8-1fixed
sid7.2.9-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcetrixie6.12.111-1DSA-6528-1
linuxsource(unstable)7.2.6-1

Notes

https://git.kernel.org/linus/d989e22ae9802c52c56ad4284d0caf26696cf6ae (7.3-rc1)

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