CVE-2026-43026: Linux kernel · netfilter: ctnetlink: zero expect NAT fields when CTA_EXPECT_NAT absent
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in fd002ff2ea030cbfb0188a11b3c60ce7f84485f4 : update Linux kernel when convenient.
Data as of 6 Nov 2026, 16:32 UTC
Rated Low by Threat Radar's AI analysis · No CVSS score from NVD or the CNA
Thin evidence
One scorer or none- 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
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-11-06.
- Patch
- Available – fixed in fd002ff2ea030cbfb0188a11b3c60ce7f84485f4, bff0f4f06f12d6d9bc565a3e1378abd4f6f5ce36, a64b7bf84b4d5ea54218c5d374ec87fff9000f43 +5
Exploitation evidence
Disclosed: evidence found.
CVE published 1 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 6 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
AI-suggested
A fix is available and has been applied in the Linux kernel commits listed in the establishedFacts.fixedVersions. Users should update to a fixed kernel version containing these commits to remediate the issue. No additional mitigation steps are indicated.
Description
A vulnerability in the Linux kernel netfilter ctnetlink component causes uninitialized NAT expectation fields to be leaked to userspace when the CTA_EXPECT_NAT attribute is absent. This occurs because the ctnetlink_alloc_expect() function allocates expectations from a slab cache without zeroing certain fields, potentially exposing stale kernel memory data.
References
- git.kernel.org/stable/c/a5a89db6981a1ddf2314bf50cb49db5a3146185f (opens in a new tab)
- git.kernel.org/stable/c/1c2ebdeff8d088a2e47ae25d7b38447249adace2 (opens in a new tab)
- git.kernel.org/stable/c/a64b7bf84b4d5ea54218c5d374ec87fff9000f43 (opens in a new tab)
- git.kernel.org/stable/c/2898080c054ea4d6ddfaaf21bbedbc229a9a8376 (opens in a new tab)
- git.kernel.org/stable/c/fd002ff2ea030cbfb0188a11b3c60ce7f84485f4 (opens in a new tab)
- git.kernel.org/stable/c/929f7a9a7aad9404a5867216c3f8738232355b38 (opens in a new tab)
- git.kernel.org/stable/c/bff0f4f06f12d6d9bc565a3e1378abd4f6f5ce36 (opens in a new tab)
- git.kernel.org/stable/c/35177c6877134a21315f37d57a5577846225623e (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)