CVE-2026-43036

Summary

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

Impact & exploitability

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products we track (1)

Recommendation

Apply the vendor fix in your normal patch cycle. Open any affected product above for its exact safe version.

Official patch: https://git.kernel.org/stable/c/cc91202fc20a44aab4c206f12a2bfe05da936051 ↗

Additional information

• NVD record
• https://git.kernel.org/stable/c/cc91202fc20a44aab4c206f12a2bfe05da936051Patch
• https://git.kernel.org/stable/c/d970341cfa5594614c7a6634886c7688b4f5cafdPatch
• https://git.kernel.org/stable/c/ddc748a391dd8642ba6b2e4fe22e7f2ddf84b7f0Patch
• https://git.kernel.org/stable/c/f7a6cd508e9e825a2c69fa9e13d41ee156852f25Patch
• https://git.kernel.org/stable/c/362bacb37d88a178bfaefc4484623eae44425a70
• https://git.kernel.org/stable/c/5057502630fbc8ce468ff617ff59af275960b537