Expired nf_tables catchall elements block insert and delete in Linux
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 4 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
The Linux kernel from 5.13 is affected by a flaw in the nf_tables netfilter subsystem. The catchall element insert and delete paths treat expired elements as active, so an expired catchall element can block re-insertion and can be retired in place of a fresh one.
Written with Claude Haiku 5.5 from the sources below · 2026-11-07
Description from the CNA
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: skip expired catchall elements on insert and delete nft_setelem_catchall_insert() looks up duplicates with nft_set_elem_active() only, while nft_set_catchall_lookup() and the dump path additionally skip expired elements. Once a catchall element with a timeout expires, this predicate drift makes it invisible to userspace dumps, yet it still blocks re-insertion: with NLM_F_EXCL the request fails with -EEXIST, and without it the request reports success but silently inserts nothing. The stale entry only goes away when the (user-tunable) gc interval elapses, so the catchall rule may silently stop matching for an arbitrarily long time after its first expiration. The delete path shows the same drift: nft_setelem_catchall_deactivate() picks the first active-next entry in the catchall list, so with an expired entry still pending GC it retires the stale entry instead of the fresh one, and it deactivates an element that userspace no longer sees instead of failing with -ENOENT. Align both walks with the lookup and dump predicates: only an element that is active and not expired counts as a duplicate or delete candidate, using the per-netns timestamp taken at transaction start, in line with the set backend .insert/.deactivate and catchall GC sync paths.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
Update the Linux kernel to a fixed version: 5.15.224, 6.1.191, 6.6.160, 6.12.112, 6.18.55, 7.2.9 or 7.3. Red Hat lists no available fix plan for Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 and Red Hat OpenShift Container Platform 5.
Written with Claude Haiku 5.5 from the sources below · 2026-11-07
- Fix · CNA Linux (Linux) Fixed in 5.15.224, 6.1.191, 6.6.160, 6.12.112, 6.18.55, 7.2.9, 7.3
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 4 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat OpenShift Container Platform 4
Timeline
- 2026-10-18 Threatist record created from CVE-2026-98484
- 2026-10-18 Alias added: GHSA-j4h7-w628-h5g3
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-20 Affected versions changed · Red Hat
- 2026-10-20 CVSS score added · Red Hat
- 2026-10-21 Fix available: Linux/Linux@5e20b39aa7844769a7a782484bc1a809ffbc513e, Linux/[email protected] · CNA
- 2026-10-21 1 new reference · CNA
- 2026-10-30 Fix available: Linux/Linux@2462ff0861f0dd5b2abdc3e95c3360d8566ab081, Linux/[email protected], Linux/[email protected] +1 · CNA
- 2026-10-30 2 new references · CNA
- 2026-11-07 Affected versions changed · Red Hat
References
Other 7
- https://git.kernel.org/stable/c/2462ff0861f0dd5b2abdc3e95c3360d8566ab081
- https://git.kernel.org/stable/c/f347d71d0d1a2157d8ecadbe1fba69cff32fce98
- https://git.kernel.org/stable/c/5e20b39aa7844769a7a782484bc1a809ffbc513e
- https://git.kernel.org/stable/c/2f07da3881525f7cbfed1ced2796c71a201505b9
- https://git.kernel.org/stable/c/12cf803edfffef96f6415f0b5dbc7ec88842ea0f
- https://git.kernel.org/stable/c/4fb8b1ccc475651e480e509de126bb9ce7f3cff9
- https://git.kernel.org/stable/c/70194dc37670bd08e44b471389861cc01bd3a3c9
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Sources
- CVE-2026-98484 · CVE Program
- CVE-2026-98484 · NVD
- FIRST EPSS
- GHSA-j4h7-w628-h5g3 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98484 · Red Hat security data · CC BY 4.0
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