gtp: add synchronize_net() in gtp_newlink() error path to prevent use-after-free
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
In 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().
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
Not affected: 7 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4
- Red Hat OpenShift Container Platform 5
Timeline
- 2026-10-02 Threatist record created from CVE-2026-89789
- 2026-10-03 Alias added: GHSA-h6q8-7j67-4q68
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-11-06 Affected versions changed · Red Hat
- 2026-11-06 CVSS score added · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/fcafb2b1430824bae4258c01a439ec97ca0c6973
- https://git.kernel.org/stable/c/3ca3da5c305caa873ddb81e8c6b118143f6dd3d1
- https://git.kernel.org/stable/c/6f815c2fb6ab20385f81c353cdad0ea3b88132af
- https://git.kernel.org/stable/c/e3b9aa0773abd5d4ed90be41ce5306c146d5b09e
- https://git.kernel.org/stable/c/fd8396cfecbd904468c71362f08aaa25f96d5337
- https://git.kernel.org/stable/c/7677eb2cbf2cc7446de474c01a6b06277c0051e5
- https://git.kernel.org/stable/c/8d85498016a5bb56339734a14c276209fa65bafc
- https://git.kernel.org/stable/c/d989e22ae9802c52c56ad4284d0caf26696cf6ae
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Sources
- CVE-2026-89789 · CVE Program
- CVE-2026-89789 · NVD
- FIRST EPSS
- GHSA-h6q8-7j67-4q68 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-89789 · Red Hat security data · CC BY 4.0
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