{"apiVersion":"1.0","identifier":"CVE-2026-72250","description":"In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_reasm: guard mac_header adjustment after IPv6 defrag nf_ct_frag6_reasm() slides the packet head forward to drop the IPv6 fragment header and then unconditionally advances skb->mac_header: skb->mac_header += sizeof(struct frag_hdr); On the NF_INET_LOCAL_OUT defrag path the skb has no link-layer header yet, so skb->mac_header is still the -not set- sentinel (u16)~0U. Adding sizeof(struct frag_hdr) wraps it to a small value (0xffff + 8 == 7), after which skb_mac_header_was_set() wrongly reports a MAC header is present and skb_mac_header() points into the headroom. The reassembler has done this unconditional add since it was introduced; it was harmless while mac_header was a bare pointer, but wrong once mac_header became a u16 offset whose unset state is the ~0U sentinel tested by skb_mac_header_was_set(). The sibling net/ipv6/reassembly.c does the same relocation and does guard the adjustment; mirror the guard here.","publishedAt":"2026-08-15T06:21:52","lastModifiedAt":"2026-08-17T06:18:27","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-72250","cvssScore":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","epssProbability":0.00169,"riskScore":0.79,"affectedProduct":"Linux kernel","affectedVersions":"unknown","vulnerabilityType":"Kernel","operatingSystems":[],"links":{"self":"https://www.redsauce.net/api/cves/CVE-2026-72250","webPages":{"es":"https://www.redsauce.net/es/cves/CVE-2026-72250","en":"https://www.redsauce.net/en/cves/CVE-2026-72250","fr":"https://www.redsauce.net/fr/cves/CVE-2026-72250","pt":"https://www.redsauce.net/pt/cves/CVE-2026-72250","de":"https://www.redsauce.net/de/cves/CVE-2026-72250","sk":"https://www.redsauce.net/sk/cves/CVE-2026-72250","el":"https://www.redsauce.net/el/cves/CVE-2026-72250"},"source":"https://nvd.nist.gov/vuln/detail/CVE-2026-72250"}}