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CVE-2026-97609

netfilter: cttimeout: prevent UAF during module unload

Products / packages Linux

Published

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Severity and exploitation

Not in CISA KEV

KEV coverage does not rule out exploitation.

KEV checked 14/11/2026, 21:30:34 UTC
Linux · CVSS:3.1 · 7
Assessment vectorCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Severity

high7.0

CVSS measures technical severity, not the likelihood of an attack.

Known exploitation

Not listed in the checked CISA KEV catalog

Absence from CISA KEV does not rule out attacks.

Public exploit

Not established by this record

Missing evidence does not mean no public exploit exists.

Remediation

Fix status not established

No structured fix or guidance is available here. Check the latest publisher advisory.

What this means

The Linux kernel's netfilter cttimeout module has a use-after-free vulnerability, affecting versions starting from 5.13. An attacker with access to the module can potentially exploit this weakness, but the impact is unclear.

Summarized by @cf/meta/llama-3.3-70b-instruct-fp8-fast. Verify details against the original sources.

Attack conditions

No attack-condition excerpt has been identified here. Review the full source description and references for authentication, network access, and configuration requirements.

Review supporting sources →

Affected versions

Check the exact model, release, and any platform requirements against your installation.

Linux · Linux

Linux

6 ranges
Linux version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

ebfbe67568a734a449203097b02c4ab884257535 → before 763787e9d43982d1082b59caeabd317343b153ea

git versions

ebfbe67568a734a449203097b02c4ab884257535 → before f664e06699829a31e95675a6864655a6c5f9904f

git versions

ebfbe67568a734a449203097b02c4ab884257535 → before 73f353bec62509c776184e49a031c6145cec0d05

git versions

ebfbe67568a734a449203097b02c4ab884257535 → before a7fdd86c386b7f7cc72a126389c2cdb55d035221

git versions

ebfbe67568a734a449203097b02c4ab884257535 → before 1f69c570a73f2dedf75ea5166d47622d5fa958c1

git versions

ebfbe67568a734a449203097b02c4ab884257535 → before fec9b1de0d02de8dafa3cc344bcb91cf28660643

git versions

unaffected

unknown

Other versions: unaffected

Linux · Linux

Linux

8 ranges
Linux version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

5.13

unaffected

0 → before 5.13

semver versions

6.1.191 → through 6.1.*

semver versions

6.6.160 → through 6.6.*

semver versions

6.12.112 → through 6.12.*

semver versions

6.18.53 → through 6.18.*

semver versions

7.2.7 → through 7.2.*

semver versions

7.3 → through *

original_commit_for_fix versions

unknown

Other versions: affected

Automatic dependency matching is unavailable for this record. Use the product evidence and publisher’s instructions to check your installation.

What to do

Compare your installed product and version with the affected versions above. A matching product name alone does not confirm exposure.

No structured fix or remediation guidance is available here. Check the full source description and vendor’s latest advisory for a patch or workaround; do not assume another version is safe.

cve.new guidance unless attributed to a publisher. This page does not inspect your installation.

Public exploit evidence

No public exploit reference is identified in the imported evidence. This is not a claim that no exploit exists.

Original source description

Read the full publisher 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.

References

6 sources
git.kernel.org/stable/c/763787e9d43982d1082b59caeabd317343b153ea
Source referenceLinux
git.kernel.org/stable/c/f664e06699829a31e95675a6864655a6c5f9904f
Source referenceLinux
git.kernel.org/stable/c/73f353bec62509c776184e49a031c6145cec0d05
Source referenceLinux
git.kernel.org/stable/c/a7fdd86c386b7f7cc72a126389c2cdb55d035221
Source referenceLinux
git.kernel.org/stable/c/1f69c570a73f2dedf75ea5166d47622d5fa958c1
Source referenceLinux
git.kernel.org/stable/c/fec9b1de0d02de8dafa3cc344bcb91cf28660643
Source referenceLinux

Inside the record

Evidence available

Package identity · not supplied
Version evidence
Remediation guidance · not supplied
Weakness classification · not supplied
Additional publishers · not supplied

Describes the evidence in this view, not whether the product is safe.

Original records

CVE-2026-97609

View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.

cve.new JSON →

Environment requirements

These conditions apply together as specified by the publisher. A matching product name alone does not establish exposure.

Linux · platform conditions

Any condition may hold

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 5.13

Before: 6.1.191

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 5.13

Before: 6.6.160

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 5.13

Before: 6.12.112

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 5.13

Before: 6.18.53

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 5.13

Before: 7.2.7

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 5.13

Before: 7.3

Applicability preview
[
  {
    "nodes": [
      {
        "operator": "OR",
        "negate": false,
        "cpeMatch": [
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "5.13",
            "versionEndExcluding": "6.1.191"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "5.13",
            "versionEndExcluding": "6.6.160"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "5.13",
            "versionEndExcluding": "6.12.112"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "5.13",
            "versionEndExcluding": "6.18.53"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "5.13",
            "versionEndExcluding": "7.2.7"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "5.13",
            "versionEndExcluding": "7.3"
          }
        ]
      }
    ]
  }
]
Contributing organizations · 1
Linux

Assigning organization

2026-10-30

Timeline

All times UTC

  1. Advisory published

    Publication date supplied by the source.

  2. Source updated

    Latest modification date supplied by the source.

  3. Last imported by cve.new

    Latest catalog import, not the date we first saw this advisory.

What changed

Follow changes
No substantive changes have been recorded here yet. History starts when cve.new observes a change after tracking is enabled; earlier edits are not reconstructed.

Large field values are marked as truncated previews. Original source snapshots remain retained.