CVE-2026-43036
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
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| sles | affected | | |
| debian | bookworm | affected | |
| debian | bullseye | affected | |
| debian | forky | fixed | 6.19.12-1 |
| debian | sid | fixed | 6.19.12-1 |
| debian | trixie | fixed | 6.12.85-1 |
| linux-kernel | affected | 6.12.81 | |
| linux-kernel | 7.0 | affected | |
| windows | affected | |
References
- https://git.kernel.org/stable/c/cc91202fc20a44aab4c206f12a2bfe05da936051
- https://git.kernel.org/stable/c/d970341cfa5594614c7a6634886c7688b4f5cafd
- https://git.kernel.org/stable/c/ddc748a391dd8642ba6b2e4fe22e7f2ddf84b7f0
- https://git.kernel.org/stable/c/f7a6cd508e9e825a2c69fa9e13d41ee156852f25
- https://www.suse.com/security/cve/CVE-2026-43036.html
- https://security-tracker.debian.org/tracker/CVE-2026-43036
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-43036
CWEs
CWE-908
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.