CVE-2026-89789

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().

Affected Software

VendorProductVersion RangeStatus
LinuxLinux459aa660eb1d8ce67080da1983bb81d716aa5a69 < fcafb2b1430824bae4258c01a439ec97ca0c6973affected
LinuxLinux459aa660eb1d8ce67080da1983bb81d716aa5a69 < 3ca3da5c305caa873ddb81e8c6b118143f6dd3d1affected
LinuxLinux459aa660eb1d8ce67080da1983bb81d716aa5a69 < 6f815c2fb6ab20385f81c353cdad0ea3b88132afaffected
LinuxLinux459aa660eb1d8ce67080da1983bb81d716aa5a69 < e3b9aa0773abd5d4ed90be41ce5306c146d5b09eaffected
LinuxLinux459aa660eb1d8ce67080da1983bb81d716aa5a69 < fd8396cfecbd904468c71362f08aaa25f96d5337affected
LinuxLinux459aa660eb1d8ce67080da1983bb81d716aa5a69 < 7677eb2cbf2cc7446de474c01a6b06277c0051e5affected
LinuxLinux459aa660eb1d8ce67080da1983bb81d716aa5a69 < 8d85498016a5bb56339734a14c276209fa65bafcaffected
LinuxLinux459aa660eb1d8ce67080da1983bb81d716aa5a69 < d989e22ae9802c52c56ad4284d0caf26696cf6aeaffected
LinuxLinux4.7affected
LinuxLinux0 < 4.7unaffected
LinuxLinux5.10.270 <= 5.10.*unaffected
LinuxLinux5.15.221 <= 5.15.*unaffected
LinuxLinux6.1.188 <= 6.1.*unaffected
LinuxLinux6.6.157 <= 6.6.*unaffected
LinuxLinux6.12.110 <= 6.12.*unaffected
LinuxLinux6.18.52 <= 6.18.*unaffected
LinuxLinux7.2.6 <= 7.2.*unaffected
LinuxLinux7.3-rc1 <= *unaffected

Weaknesses

References