CVE-2026-23458: Linux kernel · netfilter: ctnetlink: fix use-after-free in ctnetlink_dump_exp_ct()
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.8 High · fixed in f025171feef2ac65663d7986f1d5ff0c28d6b2a9 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:18 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% 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, 2026-10-16.
- Patch
- Available – fixed in f025171feef2ac65663d7986f1d5ff0c28d6b2a9, f04cc86d59906513d2d62183b882966fc0ae0390, d8cd0efbccc5cfb0a80da744a7da76e1333ab925 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 3 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
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
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 and has been applied in specific Linux kernel commits identified by the fixedVersions hashes. Users should update their Linux kernel to a version that includes these fixes. No additional mitigation steps are indicated by the vendor advisory.
Description
CVE-2026-23458 is a use-after-free vulnerability in the Linux kernel's netfilter ctnetlink subsystem. The flaw occurs in the ctnetlink_dump_exp_ct() function, where a conntrack pointer is stored but its reference is dropped prematurely during multi-round netlink dumps. This leads to dereferencing freed memory, causing a use-after-free condition. The issue is fixed by adding proper start and done callbacks to manage the conntrack reference across dump rounds.
References
- git.kernel.org/stable/c/d8cd0efbccc5cfb0a80da744a7da76e1333ab925 (opens in a new tab)
- git.kernel.org/stable/c/9821b47f669eb82791fa0b1a6ebaf9aa219bea72 (opens in a new tab)
- git.kernel.org/stable/c/bdf2724eefd4455a66863abb025bab8d3aa98c57 (opens in a new tab)
- git.kernel.org/stable/c/f04cc86d59906513d2d62183b882966fc0ae0390 (opens in a new tab)
- git.kernel.org/stable/c/f025171feef2ac65663d7986f1d5ff0c28d6b2a9 (opens in a new tab)
- git.kernel.org/stable/c/04c8907ce4e3d3e26c5e1a3e47aa5d17082cbb56 (opens in a new tab)
- git.kernel.org/stable/c/cd541f15b60e2257441398cf495d978f816d09f8 (opens in a new tab)
- git.kernel.org/stable/c/5cb81eeda909dbb2def209dd10636b51549a3f8a (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-019113.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-457936.html (opens in a new tab)