CVE-2026-89789

gtp: add synchronize_net() in gtp_newlink() error path to prevent use-after-free

State: Published
Severity: 7.8 High
Published: Sep 16, 2026
Updated: Oct 19, 2026
Reserved: Sep 11, 2026

Description

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().

Scores

CVSS	Score	Vector	Source
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	Linux

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	459aa660eb1d8ce67080da1983bb81d716aa5a69 to before fcafb2b1430824bae4258c01a439ec97ca0c6973Affected 459aa660eb1d8ce67080da1983bb81d716aa5a69 to before 3ca3da5c305caa873ddb81e8c6b118143f6dd3d1Affected 459aa660eb1d8ce67080da1983bb81d716aa5a69 to before 6f815c2fb6ab20385f81c353cdad0ea3b88132afAffected 459aa660eb1d8ce67080da1983bb81d716aa5a69 to before e3b9aa0773abd5d4ed90be41ce5306c146d5b09eAffected 459aa660eb1d8ce67080da1983bb81d716aa5a69 to before fd8396cfecbd904468c71362f08aaa25f96d5337Affected 459aa660eb1d8ce67080da1983bb81d716aa5a69 to before 7677eb2cbf2cc7446de474c01a6b06277c0051e5Affected 459aa660eb1d8ce67080da1983bb81d716aa5a69 to before 8d85498016a5bb56339734a14c276209fa65bafcAffected 459aa660eb1d8ce67080da1983bb81d716aa5a69 to before d989e22ae9802c52c56ad4284d0caf26696cf6aeAffected
LinuxLinux	4.7Affected before 4.7Not affected 5.10.270 through 5.10.Not affected 5.15.221 through 5.15.Not affected 6.1.188 through 6.1.Not affected 6.6.157 through 6.6.Not affected 6.12.110 through 6.12.Not affected 6.18.52 through 6.18.Not affected 7.2.6 through 7.2.*Not affected 7.3 and laterNot affected

Product

Versions

LinuxLinux

459aa660eb1d8ce67080da1983bb81d716aa5a69 to before fcafb2b1430824bae4258c01a439ec97ca0c6973Affected
459aa660eb1d8ce67080da1983bb81d716aa5a69 to before 3ca3da5c305caa873ddb81e8c6b118143f6dd3d1Affected
459aa660eb1d8ce67080da1983bb81d716aa5a69 to before 6f815c2fb6ab20385f81c353cdad0ea3b88132afAffected
459aa660eb1d8ce67080da1983bb81d716aa5a69 to before e3b9aa0773abd5d4ed90be41ce5306c146d5b09eAffected
459aa660eb1d8ce67080da1983bb81d716aa5a69 to before fd8396cfecbd904468c71362f08aaa25f96d5337Affected
459aa660eb1d8ce67080da1983bb81d716aa5a69 to before 7677eb2cbf2cc7446de474c01a6b06277c0051e5Affected
459aa660eb1d8ce67080da1983bb81d716aa5a69 to before 8d85498016a5bb56339734a14c276209fa65bafcAffected
459aa660eb1d8ce67080da1983bb81d716aa5a69 to before d989e22ae9802c52c56ad4284d0caf26696cf6aeAffected

LinuxLinux

4.7Affected
before 4.7Not affected
5.10.270 through 5.10.*Not affected
5.15.221 through 5.15.*Not affected
6.1.188 through 6.1.*Not affected
6.6.157 through 6.6.*Not affected
6.12.110 through 6.12.*Not affected
6.18.52 through 6.18.*Not affected
7.2.6 through 7.2.*Not affected
7.3 and laterNot affected

References

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