CVE-2026-97609netfilter: cttimeout: prevent UAF during module unload
Updated under an hour ago ()
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In the Linux kernel, the following vulnerability has been resolved: netfilter: cttimeout: prevent UAF during module unload nf_ct_set_timeout() protects the timeout hook dereference and policy lookup with rcu_read_lock(). cttimeout_exit(), however, unregisters the per-net operations before it clears the hook. This allows the following interleaving: CPU 0 CPU 1 cttimeout_exit() nf_ct_set_timeout() unregister_pernet_subsys() rcu_read_lock() kfree(pernet) h = nf_ct_timeout_hook h->timeout_find_get() nfct_timeout_pernet() The hook still points to ctnl_timeout_find_get() when CPU 1 looks up the already freed per-net timeout list. KASAN reported: BUG: KASAN: slab-use-after-free in ctnl_timeout_find_get Read of size 8 by task poc/90 Call Trace: ctnl_timeout_find_get+0x271/0x2a0 [nfnetlink_cttimeout] nf_ct_set_timeout+0x7b/0x3c0 xt_ct_tg_check+0x724/0xb20 xt_check_target+0x234/0xa90 do_ipt_set_ctl+0x570/0x1270 Allocated by task 89: __kmalloc_noprof+0x16e/0x460 ops_init+0x6d/0x420 register_pernet_operations+0x2f6/0x670 Freed by task 91: kfree+0x131/0x390 ops_undo_list+0x3d4/0x730 unregister_pernet_operations+0x232/0x490 unregister_pernet_subsys+0x1c/0x30 cttimeout_exit+0x52/0x970 [nfnetlink_cttimeout] Clear the hook and wait for existing readers before unregistering the per-net operations. This blocks new policy lookups and ensures readers that observed the hook finish before the per-net storage is freed.
- CVSS
- 7.0 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Oct 3, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from ebfbe67568a734a449203097b02c4ab884257535 before 73f353bec62509c776184e49a031c6145cec0d05; from ebfbe67568a734a449203097b02c4ab884257535 before a7fdd86c386b7f7cc72a126389c2cdb55d035221; from ebfbe67568a734a449203097b02c4ab884257535 before 1f69c570a73f2dedf75ea5166d47622d5fa958c1; from ebfbe67568a734a449203097b02c4ab884257535 before fec9b1de0d02de8dafa3cc344bcb91cf28660643 | CNA record |
References
- https://git.kernel.org/stable/c/73f353bec62509c776184e49a031c6145cec0d05
- https://git.kernel.org/stable/c/a7fdd86c386b7f7cc72a126389c2cdb55d035221
- https://git.kernel.org/stable/c/1f69c570a73f2dedf75ea5166d47622d5fa958c1
- https://git.kernel.org/stable/c/fec9b1de0d02de8dafa3cc344bcb91cf28660643
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.