CVE-2026-72250
What it is
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.
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.2% chance of exploitation in the next 30 days (EPSS).
- Fix
- No patch or advisory is linked yet. Look at mitigations or restrict exposure.
Timeline
- ReservedThe CVE id was reserved by its CNA
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.2% in the next 30 days (EPSS).
- Severity: 7.8 HIGH (CVSS).
- Fix: none linked yet, which raises it.
Details
- Published
- Last modified
- Exploit probability
- 0.2% · EPSS, next 30 days
- Record status
- Received
Attack profile CVSS 3.1 · 7.8
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-72250.md and follow it. Check whether this project is affected by CVE-2026-72250. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
References
- https://git.kernel.org/stable/c/00bdce2fda7e430d24cfbc96764a1b96deb31f82
- https://git.kernel.org/stable/c/2a95ec21824a8ad81ad660b12231456fc0ac9830
- https://git.kernel.org/stable/c/3b08fed5b7e0d5e3a25d73ef3ba09cd33ade16c9
- https://git.kernel.org/stable/c/53ef70a315420ed31581d38343684b3bf9a3c76d
- https://git.kernel.org/stable/c/6e8cd710ca35c576f5f2e5a396047c9ac61f75e5
- https://git.kernel.org/stable/c/a58230f3a7c4f6c3261786bc1efb72c42e68cd25
- https://git.kernel.org/stable/c/bbcdef2061b170af45702ce6b359c02c12acfc94
- https://git.kernel.org/stable/c/cd0d7bbc027b4d3329712cdcdeb4e5567ffd0d58