CVEvulnerability

CVE-2026-98096

7.4 HIGH Published 2026-09-25 Modified 2026-10-28 Official page ↗
Status
Analyzed
Published
2026-09-25
Last modified
2026-10-28
Assigner
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS 3.1 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)
7.4 HIGH — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H
Weaknesses
CWE-787

Description

In the Linux kernel, the following vulnerability has been resolved: ipv6: sr: restore network header before routing and forwarding ipv6_srh_rcv() runs with skb->data at the Segment Routing Header (SRH) while skb_network_header() points at the IPv6 header. When segments_left > 0, ipv6_srh_rcv() previously restored the skb->data position by pushing sizeof(struct ipv6hdr), assuming the SRH immediately followed the fixed IPv6 header. If another extension header (such as a Hop-by-Hop options header) precedes the SRH, skb_network_offset() remained negative. This led to two problems: 1. During ip6_route_input(), fib6_rules_early_flow_dissect() invokes __skb_flow_dissect() which passes the negative skb_network_offset() to flow dissection, breaking BPF and C flow dissector logic. 2. If forwarded via ip6_forward() or redirected via act_mirred, downstream handlers (like sch_fragment() or neighbour output) pass the negative offset as an unsigned length, triggering OOB memcpy or buffer overflows. Fix this by pushing -skb_network_offset(skb) before routing, ensuring skb_network_offset(skb) is 0 for route lookup / flow dissection as well as downstream forwarding. On the loopback path, pull skb_transport_offset(skb) to restore skb->data to the SRH before looping back.

Affected configurations

• linux linux kernel (>= 4.10 < 5.10.271) • linux linux kernel (>= 5.11 < 5.15.222) • linux linux kernel (>= 6.0 < 6.1.189) • linux linux kernel (>= 6.2 < 6.6.158) • linux linux kernel (>= 6.7 < 6.12.111) • linux linux kernel (>= 6.13 < 6.18.53) • linux linux kernel (>= 6.19 < 7.2.7) • linux linux kernel 7.3

Related

Weakness · CWE (1)

  • CWE-787 Out-of-bounds Write weakness

References