Skip to content
CVE PROGRAM SOURCE RECORD7.8 High

CVE-2026-72250

netfilter: nf_conntrack_reasm: guard mac_header adjustment after IPv6 defrag

Read JSON ↗CVE.org ↗
Status
Published
Published
Updated
Assigning organization
Linux

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1 to < 6e8cd710ca35c576f5f2e5a396047c9ac61f75e5affected
  • 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1 to < 2a95ec21824a8ad81ad660b12231456fc0ac9830affected
  • 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1 to < bbcdef2061b170af45702ce6b359c02c12acfc94affected
  • 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1 to < cd0d7bbc027b4d3329712cdcdeb4e5567ffd0d58affected
  • 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1 to < 53ef70a315420ed31581d38343684b3bf9a3c76daffected
  • 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1 to < a58230f3a7c4f6c3261786bc1efb72c42e68cd25affected
  • 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1 to < 00bdce2fda7e430d24cfbc96764a1b96deb31f82affected
  • 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1 to < 3b08fed5b7e0d5e3a25d73ef3ba09cd33ade16c9affected

Linux Linux

Default version status: affected

  • 2.6.15affected
  • 0 to < 2.6.15unaffected
  • 5.10.261 to ≤ 5.10.*unaffected
  • 5.15.212 to ≤ 5.15.*unaffected
  • 6.1.178 to ≤ 6.1.*unaffected
  • 6.6.145 to ≤ 6.6.*unaffected
  • 6.12.97 to ≤ 6.12.*unaffected
  • 6.18.40 to ≤ 6.18.*unaffected
  • 7.1.5 to ≤ 7.1.*unaffected
  • 7.2 to ≤ *unaffected

References