CVE-2026-43036

net: use skb_header_pointer() for TCPv4 GSO frag_off check

MEDIUM
5.5
CVSS Score
Published: May 1, 2026 at 02:15 PM UTC
Updated: October 21, 2026 at 01:18 PM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.2%

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

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

4.7 ≤ v < 6.12.816.13 ≤ v < 6.18.226.19 ≤ v < 6.19.124.77.07.0 rc17.0 rc27.0 rc37.0 rc47.0 rc57.0 rc6cbc53e08a793b073e79f42ca33f1f3568703540d
Vendor states this is fixed in cc91202fc20a44aab4c206f12a2bfe05da936051 (fixed)
Vendor states this is fixed in d970341cfa5594614c7a6634886c7688b4f5cafd (fixed)
Vendor states this is fixed in ddc748a391dd8642ba6b2e4fe22e7f2ddf84b7f0 (fixed)
Vendor states this is fixed in f7a6cd508e9e825a2c69fa9e13d41ee156852f25 (fixed)
Vendor states this is fixed in 4.7 (unaffected)
Vendor states this is fixed in 6.12.81 (unaffected)
Vendor states this is fixed in 6.18.22 (unaffected)
Vendor states this is fixed in 6.19.12 (unaffected)
Vendor states this is fixed in 6.6.160 (unaffected)
Vendor states this is fixed in 7.0 (unaffected)

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-908

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