CVE-2026-43036

MEDIUM

net: use skb_header_pointer() for TCPv4 GSO frag_off check

Title source: cna
STIX 2.1

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

Scores

CVSS v3 5.5
EPSS 0.0001
EPSS Percentile 2.2%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Details

CWE
CWE-908
Status published
Products (12)
Linux/Linux < 4.7
Linux/Linux 4.7
Linux/Linux 6.12.81 - 6.12.*
Linux/Linux 6.18.22 - 6.18.*
Linux/Linux 6.19.12 - 6.19.*
Linux/Linux 7.0
Linux/Linux cbc53e08a793b073e79f42ca33f1f3568703540d - cc91202fc20a44aab4c206f12a2bfe05da936051
Linux/Linux cbc53e08a793b073e79f42ca33f1f3568703540d - d970341cfa5594614c7a6634886c7688b4f5cafd
Linux/Linux cbc53e08a793b073e79f42ca33f1f3568703540d - ddc748a391dd8642ba6b2e4fe22e7f2ddf84b7f0
Linux/Linux cbc53e08a793b073e79f42ca33f1f3568703540d - f7a6cd508e9e825a2c69fa9e13d41ee156852f25
... and 2 more
Published May 01, 2026
Tracked Since May 01, 2026