netfilter: cttimeout: prevent UAF during module unload
Summary
| CVE | CVE-2026-97609 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-25 11:17:14 UTC |
| Updated | 2026-09-25 15:18:01 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 7 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS: 0.001390000 probability, percentile 0.026870000 (date 2026-09-27)
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | Secondary | 7 | HIGH | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H |
| 3.1 | CNA | DECLARED | 7 | HIGH | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H |
CVSS v3.1 Breakdown
Attack Vector
LocalAttack Complexity
HighPrivileges Required
LowUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected ebfbe67568a734a449203097b02c4ab884257535 a7fdd86c386b7f7cc72a126389c2cdb55d035221 git | Not specified |
| CNA | Linux | Linux | affected ebfbe67568a734a449203097b02c4ab884257535 1f69c570a73f2dedf75ea5166d47622d5fa958c1 git | Not specified |
| CNA | Linux | Linux | affected ebfbe67568a734a449203097b02c4ab884257535 fec9b1de0d02de8dafa3cc344bcb91cf28660643 git | Not specified |
| CNA | Linux | Linux | affected 5.13 | Not specified |
| CNA | Linux | Linux | unaffected 5.13 semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.53 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.2.7 7.2.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.3-rc3 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/1f69c570a73f2dedf75ea5166d47622d5fa958c1 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/a7fdd86c386b7f7cc72a126389c2cdb55d035221 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/fec9b1de0d02de8dafa3cc344bcb91cf28660643 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.