CVE-2026-72250netfilter: nf_conntrack_reasm: guard mac_header adjustment after IPv6 defrag
- 7.8HighCVSS base score
- 0.17%Exploitation in 30 daysEPSS · top 94% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By Linux
- 6 days later
· 6 days later
Published
- 2 months later
· 2 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Received | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.17% · top 94% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Affected products
- affected 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1 – < 6e8cd710ca35c576f5f2e5a396047c9ac61f75e5
- affected 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1 – < 2a95ec21824a8ad81ad660b12231456fc0ac9830
- affected 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1 – < bbcdef2061b170af45702ce6b359c02c12acfc94
- affected 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1 – < cd0d7bbc027b4d3329712cdcdeb4e5567ffd0d58
- affected 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1 – < 53ef70a315420ed31581d38343684b3bf9a3c76d
- affected 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1 – < a58230f3a7c4f6c3261786bc1efb72c42e68cd25
- affected 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1 – < 00bdce2fda7e430d24cfbc96764a1b96deb31f82
- affected 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1 – < 3b08fed5b7e0d5e3a25d73ef3ba09cd33ade16c9
- affected 2.6.15
- unaffected < 2.6.15
- unaffected 5.10.261 – ≤ 5.10.*
- unaffected 5.15.212 – ≤ 5.15.*
- unaffected 6.1.178 – ≤ 6.1.*
- unaffected 6.6.145 – ≤ 6.6.*
- unaffected 6.12.97 – ≤ 6.12.*
- unaffected 6.18.40 – ≤ 6.18.*
- unaffected 7.1.5 – ≤ 7.1.*
- unaffected 7.2 – ≤ *
References
References8
- https://git.kernel.org/stable/c/6e8cd710ca35c576f5f2e5a396047c9ac61f75e5 (opens in a new tab)
- https://git.kernel.org/stable/c/2a95ec21824a8ad81ad660b12231456fc0ac9830 (opens in a new tab)
- https://git.kernel.org/stable/c/bbcdef2061b170af45702ce6b359c02c12acfc94 (opens in a new tab)
- https://git.kernel.org/stable/c/cd0d7bbc027b4d3329712cdcdeb4e5567ffd0d58 (opens in a new tab)
- https://git.kernel.org/stable/c/53ef70a315420ed31581d38343684b3bf9a3c76d (opens in a new tab)
- https://git.kernel.org/stable/c/a58230f3a7c4f6c3261786bc1efb72c42e68cd25 (opens in a new tab)
- https://git.kernel.org/stable/c/00bdce2fda7e430d24cfbc96764a1b96deb31f82 (opens in a new tab)
- https://git.kernel.org/stable/c/3b08fed5b7e0d5e3a25d73ef3ba09cd33ade16c9 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-59149 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-72250)Record last updated .