CVE-2026-43036

Published: May 2, 2026Last modified: May 2, 2026

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

Severity score breakdown

Status

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