CVE-2026-72250: Linux kernel · netfilter: nf_conntrack_reasm: guard mac_header adjustment after IPv6 defrag
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 5.15.0-1117.124~20.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 15:59 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1117.124~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1122.131~20.04.1 +42
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 15 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available and should be applied to affected Linux kernel versions. The vendor advisory from Ubuntu confirms that this and other kernel vulnerabilities have been fixed. Users should update their Linux kernel packages to the fixed versions as provided by their distribution. No additional mitigation steps are indicated beyond applying the official fix.
Description
A vulnerability in the Linux kernel's netfilter nf_conntrack_reasm component was resolved. The issue involves incorrect adjustment of the mac_header offset after IPv6 defragmentation, which could cause the mac_header pointer to wrap incorrectly and lead to improper packet handling. This flaw was introduced when the mac_header changed from a pointer to a u16 offset, causing the system to mistakenly report a MAC header where none exists. The vulnerability affects specific Linux kernel versions and has been addressed by adding a guard to the mac_header adjustment similar to the sibling IPv6 reassembly code.
References
- nvd.nist.gov/vuln/detail/CVE-2026-72250 (opens in a new tab)
- git.kernel.org/stable/c/00bdce2fda7e430d24cfbc96764a1b96deb31f82 (opens in a new tab)
- git.kernel.org/stable/c/2a95ec21824a8ad81ad660b12231456fc0ac9830 (opens in a new tab)
- git.kernel.org/stable/c/3b08fed5b7e0d5e3a25d73ef3ba09cd33ade16c9 (opens in a new tab)
- git.kernel.org/stable/c/53ef70a315420ed31581d38343684b3bf9a3c76d (opens in a new tab)
- git.kernel.org/stable/c/6e8cd710ca35c576f5f2e5a396047c9ac61f75e5 (opens in a new tab)
- git.kernel.org/stable/c/a58230f3a7c4f6c3261786bc1efb72c42e68cd25 (opens in a new tab)
- git.kernel.org/stable/c/bbcdef2061b170af45702ce6b359c02c12acfc94 (opens in a new tab)
- git.kernel.org/stable/c/cd0d7bbc027b4d3329712cdcdeb4e5567ffd0d58 (opens in a new tab)
- ubuntu.com/security/CVE-2026-72250 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-72250 (opens in a new tab)
- git.kernel.org/linus/3b08fed5b7e0d5e3a25d73ef3ba09cd33ade16c9 (opens in a new tab)
- ubuntu.com/security/notices/USN-8876-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8878-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8879-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8877-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8875-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8888-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8889-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8887-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8886-1 (opens in a new tab)