CVE-2026-97609
Full vulnerability record from the local CVENow database.
Description
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.
View original CVE JSON
{
"id": "CVE-2026-97609",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-09-25T11:17:14.987",
"lastModified": "2026-10-30T13:21:09.487",
"vulnStatus": "Received",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: cttimeout: prevent UAF during module unload\n\nnf_ct_set_timeout() protects the timeout hook dereference and policy lookup\nwith rcu_read_lock(). cttimeout_exit(), however, unregisters the per-net\noperations before it clears the hook.\n\nThis allows the following interleaving:\n\n CPU 0 CPU 1\n cttimeout_exit() nf_ct_set_timeout()\n unregister_pernet_subsys() rcu_read_lock()\n kfree(pernet) h = nf_ct_timeout_hook\n h->timeout_find_get()\n nfct_timeout_pernet()\n\nThe hook still points to ctnl_timeout_find_get() when CPU 1 looks up the\nalready freed per-net timeout list. KASAN reported:\n\n BUG: KASAN: slab-use-after-free in ctnl_timeout_find_get\n Read of size 8 by task poc/90\n Call Trace:\n ctnl_timeout_find_get+0x271/0x2a0 [nfnetlink_cttimeout]\n nf_ct_set_timeout+0x7b/0x3c0\n xt_ct_tg_check+0x724/0xb20\n xt_check_target+0x234/0xa90\n do_ipt_set_ctl+0x570/0x1270\n Allocated by task 89:\n __kmalloc_noprof+0x16e/0x460\n ops_init+0x6d/0x420\n register_pernet_operations+0x2f6/0x670\n Freed by task 91:\n kfree+0x131/0x390\n ops_undo_list+0x3d4/0x730\n unregister_pernet_operations+0x232/0x490\n unregister_pernet_subsys+0x1c/0x30\n cttimeout_exit+0x52/0x970 [nfnetlink_cttimeout]\n\nClear the hook and wait for existing readers before unregistering the\nper-net operations. This blocks new policy lookups and ensures readers that\nobserved the hook finish before the per-net storage is freed."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"net/netfilter/nfnetlink_cttimeout.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "ebfbe67568a734a449203097b02c4ab884257535",
"lessThan": "763787e9d43982d1082b59caeabd317343b153ea",
"versionType": "git",
"status": "affected"
},
{
"version": "ebfbe67568a734a449203097b02c4ab884257535",
"lessThan": "f664e06699829a31e95675a6864655a6c5f9904f",
"versionType": "git",
"status": "affected"
},
{
"version": "ebfbe67568a734a449203097b02c4ab884257535",
"lessThan": "73f353bec62509c776184e49a031c6145cec0d05",
"versionType": "git",
"status": "affected"
},
{
"version": "ebfbe67568a734a449203097b02c4ab884257535",
"lessThan": "a7fdd86c386b7f7cc72a126389c2cdb55d035221",
"versionType": "git",
"status": "affected"
},
{
"version": "ebfbe67568a734a449203097b02c4ab884257535",
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"versionType": "git",
"status": "affected"
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{
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"lessThan": "fec9b1de0d02de8dafa3cc344bcb91cf28660643",
"versionType": "git",
"status": "affected"
}
]
},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"net/netfilter/nfnetlink_cttimeout.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "5.13",
"status": "affected"
},
{
"version": "0",
"lessThan": "5.13",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.1.191",
"lessThanOrEqual": "6.1.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.6.160",
"lessThanOrEqual": "6.6.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.12.112",
"lessThanOrEqual": "6.12.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.18.53",
"lessThanOrEqual": "6.18.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.2.7",
"lessThanOrEqual": "7.2.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.3",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
"baseScore": 7.0,
"baseSeverity": "HIGH",
"attackVector": "LOCAL",
"attackComplexity": "HIGH",
"privilegesRequired": "LOW",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 1.0,
"impactScore": 5.9
}
]
},
"references": [
{
"url": "https://git.kernel.org/stable/c/1f69c570a73f2dedf75ea5166d47622d5fa958c1",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/73f353bec62509c776184e49a031c6145cec0d05",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/763787e9d43982d1082b59caeabd317343b153ea",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/a7fdd86c386b7f7cc72a126389c2cdb55d035221",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
"url": "https://git.kernel.org/stable/c/f664e06699829a31e95675a6864655a6c5f9904f",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
"url": "https://git.kernel.org/stable/c/fec9b1de0d02de8dafa3cc344bcb91cf28660643",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
]
}