CVE-2026-98096
Analyzed
Analyzed - Analysis Complete
Buffer Overflow in Linux Kernel IPv6 Segment Routing
Vulnerability report for CVE-2026-98096, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-09-25
Last updated on: 2026-10-28
Assigner: kernel.org
Description
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.
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | From 6.19 (inc) to 7.2.7 (exc) |
| linux | linux_kernel | 7.3 |
| linux | linux_kernel | From 6.13 (inc) to 6.18.53 (exc) |
| linux | linux_kernel | From 6.7 (inc) to 6.12.111 (exc) |
| linux | linux_kernel | From 5.11 (inc) to 5.15.222 (exc) |
| linux | linux_kernel | From 6.0 (inc) to 6.1.189 (exc) |
| linux | linux_kernel | From 6.2 (inc) to 6.6.158 (exc) |
| linux | linux_kernel | From 4.10 (inc) to 5.10.271 (exc) |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-787 | The product writes data past the end, or before the beginning, of the intended buffer. |
