netfilter: ipset: Don't use test_bit() in lockless RCU readers in hash types
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 5 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: netfilter: ipset: Don't use test_bit() in lockless RCU readers in hash types Sashiko pointed out that there are a few lockless RCU readers using test_bit() which is a relaxed atomic operation and provides no memory barrier guarantees. Use test_bit_acquire() instead where the operation may run parallel with add/del/gc, i.e. is not one from the next cases - protected by region lock - in a set destroy phase - in a new/temporary set creation phase
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1.5, 7.2
Vendor assessments
Red Hat
Red Hat rating: Moderate. 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 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix yet |
| Red Hat Enterprise Linux 8 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-72436
- 2026-10-03 Alias added: GHSA-6x4x-6p4p-6f5f
- 2026-10-16 CISA SSVC decision points changed
- 2026-10-26 Affected versions changed · Red Hat
- 2026-10-26 CVSS score changed · Red Hat
References
Other 6
- https://git.kernel.org/stable/c/c107233d2ff4fd7cef5d02f9124b99194957a710
- https://git.kernel.org/stable/c/6329d3a9afe715fddda0460cfa46b496d61c2fe0
- https://git.kernel.org/stable/c/7445fe965b7d8756070a40e80f8b73348ccda1d7
- https://git.kernel.org/stable/c/c4d257734e91bfcdc71d41843392dd6400b5bb1b
- https://git.kernel.org/stable/c/3219d74e4536658c937fd878a327257b86ce80dd
- https://git.kernel.org/stable/c/e4b4984e28c16406ecb318444dea4a8bf47def3e
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Sources
- CVE-2026-72436 · CVE Program
- CVE-2026-72436 · NVD
- FIRST EPSS
- GHSA-6x4x-6p4p-6f5f · GitHub Advisory Database · CC BY 4.0
- CVE-2026-72436 · Red Hat security data · CC BY 4.0
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