CVE-2026-43035: Linux kernel · net: sched: cls_api: fix tc_chain_fill_node to initialize tcm_info to zero to prevent
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in e35f5195cd44ff4053fbc5d71ea97681728a0099 : update Linux kernel when convenient.
Data as of 6 Nov 2026, 16:21 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 e35f5195cd44ff4053fbc5d71ea97681728a0099, e6e3eb5ee89ac4c163d46429391c889a1bb5e404, d6db08484c6cb3d4ad696246f9d288eceba2a078 +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
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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 the Linux kernel. The vulnerability is resolved by zero-initializing the tcm_info field in the affected function. Users should update to a Linux kernel version that includes the fix identified by the provided commit hashes. No additional mitigation steps are necessary once the kernel is updated.
Description
A vulnerability in the Linux kernel's network scheduler API (cls_api) was fixed by ensuring the tcm_info field in struct tcmsg is zero-initialized. Previously, this field was left uninitialized, causing kernel heap memory to be leaked to userspace via netlink messages. The fix involves zeroing tcm_info alongside other initialized fields to prevent this information leak.
References
- git.kernel.org/stable/c/903c3405cfcc7700260e456ab66a5867586c9e69 (opens in a new tab)
- git.kernel.org/stable/c/71a3eda7e850ae844cb8993065f4e410c11a46ce (opens in a new tab)
- git.kernel.org/stable/c/4ae5d23f51fb91d7d1140c6f1ba77ab0756054c3 (opens in a new tab)
- git.kernel.org/stable/c/e35f5195cd44ff4053fbc5d71ea97681728a0099 (opens in a new tab)
- git.kernel.org/stable/c/d6db08484c6cb3d4ad696246f9d288eceba2a078 (opens in a new tab)
- git.kernel.org/stable/c/906997ea3766c24fbbf9cc4bf17c047315bbd138 (opens in a new tab)
- git.kernel.org/stable/c/1091b3c174441a52fdbb92e2fe00338f9371a91c (opens in a new tab)
- git.kernel.org/stable/c/e6e3eb5ee89ac4c163d46429391c889a1bb5e404 (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)