CVE Catalog

CVE-2026-98096

HighCVSS 7.4
Published: Updated: Translated: NVD NIST

Summary

In the Linux kernel, a problem in IPv6 Segment Routing where the network header was not properly restored before routing and forwarding was fixed. Previously, when the SRH did not immediately follow the IPv6 header, the network offset could be negative, potentially leading to buffer overflows during forwarding.

Risk Assessment

The vulnerability could lead to buffer overflows or other crashes during IPv6 SR packet processing, potentially disrupting network services or enabling remote code execution.

Recommendation

Update the Linux kernel to a version containing the fix. Monitor kernel logs for IPv6 SR-related errors.

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Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS