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VulnerabilityPublished Updated

CVE-2026-43036: Linux kernel · net: use skb_header_pointer() for TCPv4 GSO frag_off check

Source GCVE Database

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Authoritative record:CVE-2026-43036· Low

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

CVSS 3.1 base score
5.5Low
How severe the flaw is on the 0–10 CVSS scale.

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:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 1 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ cbc53e08a793b073e79f42ca33f1f3568703540d, < f7a6cd508e9e825a2c69fa9e13d41ee156852f25
Fixed in
  • f7a6cd508e9e825a2c69fa9e13d41ee156852f25
LinuxLinuxAffected
  • ≥ cbc53e08a793b073e79f42ca33f1f3568703540d, < ddc748a391dd8642ba6b2e4fe22e7f2ddf84b7f0
Fixed in
  • ddc748a391dd8642ba6b2e4fe22e7f2ddf84b7f0
LinuxLinuxAffected
  • ≥ cbc53e08a793b073e79f42ca33f1f3568703540d, < d970341cfa5594614c7a6634886c7688b4f5cafd
Fixed in
  • d970341cfa5594614c7a6634886c7688b4f5cafd
LinuxLinuxAffected
  • ≥ cbc53e08a793b073e79f42ca33f1f3568703540d, < cc91202fc20a44aab4c206f12a2bfe05da936051
Fixed in
  • cc91202fc20a44aab4c206f12a2bfe05da936051
LinuxLinuxAffected
  • ≥ cbc53e08a793b073e79f42ca33f1f3568703540d, < 5057502630fbc8ce468ff617ff59af275960b537
Fixed in
  • 5057502630fbc8ce468ff617ff59af275960b537
LinuxLinuxAffected
  • ≥ cbc53e08a793b073e79f42ca33f1f3568703540d, < 362bacb37d88a178bfaefc4484623eae44425a70
Fixed in
  • 362bacb37d88a178bfaefc4484623eae44425a70

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

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