GHSA-H6Q8-7J67-4Q68
Vulnerability from github – Published: 2026-09-16 09:30 – Updated: 2026-09-16 15:30In 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: 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().
{
"affected": [],
"aliases": [
"CVE-2026-89789"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-16T09:17:09Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ngtp: add synchronize_net() in gtp_newlink() error path to prevent use-after-free\n\ngtp_newlink()\u0027s error path frees tid_hash and addr_hash without\nwaiting for an RCU grace period after clearing sk_user_data. 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 \u003cIRQ\u003e\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().",
"id": "GHSA-h6q8-7j67-4q68",
"modified": "2026-09-16T15:30:57Z",
"published": "2026-09-16T09:30:30Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89789"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3ca3da5c305caa873ddb81e8c6b118143f6dd3d1"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6f815c2fb6ab20385f81c353cdad0ea3b88132af"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7677eb2cbf2cc7446de474c01a6b06277c0051e5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8d85498016a5bb56339734a14c276209fa65bafc"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d989e22ae9802c52c56ad4284d0caf26696cf6ae"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e3b9aa0773abd5d4ed90be41ce5306c146d5b09e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fcafb2b1430824bae4258c01a439ec97ca0c6973"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fd8396cfecbd904468c71362f08aaa25f96d5337"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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