CVE-2026-23231: Linux kernel · netfilter: nf_tables: fix use-after-free in nf_tables_addchain()
Affects Linux kernelSource CVE Database V5
Public exploit available (Exploit-DB) · CVSS 7.8 High · fixed in f3fe58ce37926a10115ede527d59b91bcc05400a : patch Linux kernel as a priority.
Data as of 26 Oct 2026, 14:18 UTC
- EPSS
- 1.0% chance of exploitation in 30 days – higher than 63% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-06-16.
- Patch
- Available – fixed in f3fe58ce37926a10115ede527d59b91bcc05400a, dbd0af8083dd201f07c49110b2ee93710abdff28, 7017745068a9068904e1e7a1b170a5785647cc81 +3
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
t = 0 is the CVE’s publication on cve.org
Disclosed: evidence found.
CVE published 4 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: evidence found.
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
Timeline
CVE ID reserved
by kernel.org
, 50 days before disclosure
CVE published
on cve.org
, t = 0
First Exploit-DB entry (opens in a new tab)
Linux nf_tables 6.19.3 - Local Privilege Escalation
, 61 days after disclosure
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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AI-suggested
A fix is available in the Linux kernel as indicated by the fixed commit versions. Users and administrators should update to a patched kernel version containing these fixes. Since this is a kernel-level vulnerability, applying the official kernel updates is the recommended remediation. No additional mitigations are specified or required beyond applying the patch.
Description
CVE-2026-23231 is a use-after-free vulnerability in the Linux kernel's netfilter nf_tables subsystem, specifically in the nf_tables_addchain() function. The flaw occurs when an error during hook registration leads to premature freeing of a chain without waiting for all readers to finish, causing potential memory corruption. This affects control-plane operations and packet processing paths. The vulnerability has been fixed by adding an RCU synchronization call to ensure safe memory reclamation.
References
- git.kernel.org/stable/c/2a6586ecfa4ce1413daaafee250d2590e05f1a33 (opens in a new tab)
- git.kernel.org/stable/c/7017745068a9068904e1e7a1b170a5785647cc81 (opens in a new tab)
- git.kernel.org/stable/c/f3fe58ce37926a10115ede527d59b91bcc05400a (opens in a new tab)
- git.kernel.org/stable/c/dbd0af8083dd201f07c49110b2ee93710abdff28 (opens in a new tab)
- git.kernel.org/stable/c/2f9a4ffeb763aec822f8ff3d1e82202d27d46d4b (opens in a new tab)
- git.kernel.org/stable/c/71e99ee20fc3f662555118cf1159443250647533 (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-082556.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-253495.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-019113.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-457936.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-784472.html (opens in a new tab)