CVE-2026-43036

Medium

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

Package Linux Kernel
Published 2026-05-01
Last modified 2026-05-08
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

5.5

out of 10
Medium
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness type

CWE-908

CVE-2026-43036 is classified as CWE-908

See CWE-908 on MITRE CWE for full details on this weakness type.

Affected versions

Linux kernel versions 4.7 and later are affected. Fixed in 6.12.81, 6.18.22, 6.19.12, 7.0 and their respective stable series.

Affected from
≥ 4.7
Fixed in
✓ 6.12.81 6.12.x ✓ 6.18.22 6.18.x ✓ 6.19.12 6.19.x ✓ 7.0

References

The following references provide additional information about CVE-2026-43036 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

4 patch commits total View all on NVD

Frequently asked questions

  • What is CVE-2026-43036?

    CVE-2026-43036 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 4.7 onward and has been patched in 6.12.81, 6.18.22, 6.19.12 and others. CVE-2026-43036 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2026-43036?

    CVE-2026-43036 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H .

  • Is there a patch available for CVE-2026-43036?

    Yes — CVE-2026-43036 has been patched. Fixed versions include 6.12.81, 6.18.22, 6.19.12 and others. If you are running Linux kernel 4.7 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2026-43036 actively exploited?

    No — CVE-2026-43036 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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