CVE-2026-89789

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().

CVSS v3 7.8 HIGH

7.8^/10

CVSS v3 : HIGH

Vector :

Exploitability : 1.8 / Impact : 5.9

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://git.kernel.org/stable/c/3ca3da5c305caa873ddb81e8c6b118143f6dd3d1
https://git.kernel.org/stable/c/6f815c2fb6ab20385f81c353cdad0ea3b88132af
https://git.kernel.org/stable/c/7677eb2cbf2cc7446de474c01a6b06277c0051e5
https://git.kernel.org/stable/c/8d85498016a5bb56339734a14c276209fa65bafc
https://git.kernel.org/stable/c/d989e22ae9802c52c56ad4284d0caf26696cf6ae
https://git.kernel.org/stable/c/e3b9aa0773abd5d4ed90be41ce5306c146d5b09e
https://git.kernel.org/stable/c/fcafb2b1430824bae4258c01a439ec97ca0c6973
https://git.kernel.org/stable/c/fd8396cfecbd904468c71362f08aaa25f96d5337

Configurations

No configuration.

History

16 Sep 2026, 15:18

Type	Values Removed	Values Added
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 7.8

Information

Published : 2026-09-16 09:17

Updated : 2026-09-16 15:18

NVD link : CVE-2026-89789

Mitre link : CVE-2026-89789

CVE.ORG link : CVE-2026-89789

JSON object : View

Products Affected

No product.

CWE

No CWE.

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A\nconcurrent gtp_encap_recv() in softirq may still hold the gtp_dev\npointer obtained via rcu_dereference_sk_user_data() and access the\nfreed memory.\n\n BUG: KASAN: slab-use-after-free in gtp0_pdp_find+0x1f6/0x200 (gtp.c:152)\n Call Trace:\n <IRQ>\n gtp0_pdp_find+0x1f6/0x200\n gtp_encap_recv+0x527/0x24b0\n udp_queue_rcv_one_skb+0x75f/0xc10\n\nAdd synchronize_net() before the kfree calls in out_hashtable, which\ncovers all error paths from both gtp_encap_enable() and\ngtp_create_sockets()."}], "lastModified": "2026-09-16T15:18:09.107", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}