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().
Analysis
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Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||||||||||||||
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| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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No vendor fix or workaround currently provided.
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Wed, 16 Sep 2026 09:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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(). | |
| Title | gtp: add synchronize_net() in gtp_newlink() error path to prevent use-after-free | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-16T08:48:25.689Z
Reserved: 2026-09-11T19:38:34.766Z
Link: CVE-2026-89789
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-16T09:17:09.697
Modified: 2026-09-16T09:17:09.697
Link: CVE-2026-89789
Redhat
No data.
OpenCVE Enrichment
No data.
No weakness.