Description
In the Linux kernel, the following vulnerability has been resolved: ip6_tunnel: clear skb2->cb[] in ip4ip6_err() Oskar Kjos reported the following problem. ip4ip6_err() calls icmp_send() on a cloned skb whose cb[] was written by the IPv6 receive path as struct inet6_skb_parm. icmp_send() passes IPCB(skb2) to __ip_options_echo(), which interprets that cb[] region as struct inet_skb_parm (IPv4). The layouts differ: inet6_skb_parm.nhoff at offset 14 overlaps inet_skb_parm.opt.rr, producing a non-zero rr value. __ip_options_echo() then reads optlen from attacker-controlled packet data at sptr[rr+1] and copies that many bytes into dopt->__data, a fixed 40-byte stack buffer (IP_OPTIONS_DATA_FIXED_SIZE). To fix this we clear skb2->cb[], as suggested by Oskar Kjos. Also add minimal IPv4 header validation (version == 4, ihl >= 5).
INFO
Published Date :
2026-05-01T14:15:35.314Z
Last Modified :
2026-05-03T05:46:16.322Z
Source :
Linux
AFFECTED PRODUCTS
The following products are affected by CVE-2026-43037 vulnerability.
| Vendors | Products |
|---|---|
| Linux |
|
REFERENCES
Here, you will find a curated list of external links that provide in-depth information to CVE-2026-43037.
