CVE-2026-72250: netfilter: nf_conntrack_reasm: guard mac_header adjustment after IPv6 defrag
Vulnerability summary
CVE-2026-72250 is a high (CVSS 7.8) vulnerability in linux. EPSS estimates a 0.17% chance of exploitation in the next 30 days, higher than 6.2% of scored vulnerabilities.
Not severe (CVSS 7.8, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 20 · Related 20Timeline
- 15-08-2026PublishedVulnerability first disclosed.
- 16-10-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
4 scores · 4 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- NVDNIST7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.17%
Chance of exploitation in the next 30 days
Percentile
6%
Versus all other CVEs
30-day change
Decrease -0.01 pp
From 0.18% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeNo weakness data has been published for this record.
Affected systems
Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu169 products
- linuxAll versions (No fix recorded) | < 5.15.0-198.208 | < 6.8.0-147.147 | < 7.0.0-38.38
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 5.15.0-1117.124 | < 6.8.0-1067.70 | < 7.0.0-1014.14
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Debian1 product
- linux< 6.1.180-1 | < 6.12.100-1 | < 7.1.5-1
Linux1 product
- linux≥ 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1, < 6e8cd710ca35c576f5f2e5a396047c9ac61f75e5 | ≥ 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1, < 2a95ec21824a8ad81ad660b12231456fc0ac9830 | ≥ 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1, < bbcdef2061b170af45702ce6b359c02c12acfc94 | ≥ 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1, < cd0d7bbc027b4d3329712cdcdeb4e5567ffd0d58 | ≥ 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1, < 53ef70a315420ed31581d38343684b3bf9a3c76d | ≥ 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1, < a58230f3a7c4f6c3261786bc1efb72c42e68cd25 | ≥ 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1, < 00bdce2fda7e430d24cfbc96764a1b96deb31f82 | ≥ 9fb9cbb1082d6b31fb45aa1a14432449a0df6cf1, < 3b08fed5b7e0d5e3a25d73ef3ba09cd33ade16c9 | 2.6.15
3 vendors · 171 products
