CVE-2026-43036: Linux kernel · net: use skb_header_pointer() for TCPv4 GSO frag_off check
Source GCVE Database
Not known to be exploited · CVSS 5.5 Low · fixed in f7a6cd508e9e825a2c69fa9e13d41ee156852f25 : update Linux kernel when convenient.
Data as of 30 Oct 2026, 16:33 UTC
Thin evidence
One scorer or none- Patch
- Available – fixed in f7a6cd508e9e825a2c69fa9e13d41ee156852f25, ddc748a391dd8642ba6b2e4fe22e7f2ddf84b7f0, d970341cfa5594614c7a6634886c7688b4f5cafd +3
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation 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 30 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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Description
In the Linux kernel, the following vulnerability has been resolved: net: use skb_header_pointer() for TCPv4 GSO frag_off check Syzbot reported a KMSAN uninit-value warning in gso_features_check() called from netif_skb_features() [1]. gso_features_check() reads iph->frag_off to decide whether to clear mangleid_features. Accessing the IPv4 header via ip_hdr()/inner_ip_hdr() can rely on skb header offsets that are not always safe for direct dereference on packets injected from PF_PACKET paths. Use skb_header_pointer() for the TCPv4 frag_off check so the header read is robust whether data is already linear or needs copying. [1] https://syzkaller.appspot.com/bug?extid=1543a7d954d9c6d00407
References
- nvd.nist.gov/vuln/detail/CVE-2026-43036 (opens in a new tab)
- git.kernel.org/stable/c/362bacb37d88a178bfaefc4484623eae44425a70 (opens in a new tab)
- git.kernel.org/stable/c/5057502630fbc8ce468ff617ff59af275960b537 (opens in a new tab)
- git.kernel.org/stable/c/cc91202fc20a44aab4c206f12a2bfe05da936051 (opens in a new tab)
- git.kernel.org/stable/c/d970341cfa5594614c7a6634886c7688b4f5cafd (opens in a new tab)
- git.kernel.org/stable/c/ddc748a391dd8642ba6b2e4fe22e7f2ddf84b7f0 (opens in a new tab)
- git.kernel.org/stable/c/f7a6cd508e9e825a2c69fa9e13d41ee156852f25 (opens in a new tab)