CVE-2026-53238: Linux kernel · netlabel: validate unlabeled address and mask attribute lengths
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 5.15.0-1117.124~20.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% 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 +68
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Jun 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 has been released in Linux kernel versions 5.15.0-195.205~20.04.1 and later. Users and administrators should update to one of the fixed kernel versions to remediate this vulnerability. No additional mitigation steps are required beyond applying the official fix.
Description
A vulnerability in the Linux kernel's netlabel subsystem was resolved that involved improper validation of the mask attribute length for unlabeled IPv4/IPv6 addresses. The function netlbl_unlabel_addrinfo_get() used the address attribute length to determine how to read the attribute data but did not validate the mask attribute length independently. This could allow a crafted Generic Netlink request to provide a valid address attribute with a shorter mask attribute, potentially causing incorrect memory reads. The issue was fixed by enforcing exact length checks on these attributes during policy validation.
References
- ubuntu.com/security/CVE-2026-53238 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-53238 (opens in a new tab)
- git.kernel.org/linus/9772589b57e44aedc240211c5c3f7a684a034d3a (opens in a new tab)
- git.kernel.org/stable/c/07a18f5c90dd3d586b73242f5a5bbf0a72f2fdc6 (opens in a new tab)
- git.kernel.org/stable/c/0c4bb32ad7fdc2dc6a8050f41eb04d4bda56b6c8 (opens in a new tab)
- git.kernel.org/stable/c/672f0f3b8f875ffe6525a37847eafa7648c4c0c6 (opens in a new tab)
- git.kernel.org/stable/c/71c52da13c3737493b42d20d9f33de34e03b3156 (opens in a new tab)
- git.kernel.org/stable/c/95bda3eac0b1454c2cee98d58d9ba6dd8391e843 (opens in a new tab)
- git.kernel.org/stable/c/975a84fd741440853380d37465b6e226cf47254c (opens in a new tab)
- git.kernel.org/stable/c/9772589b57e44aedc240211c5c3f7a684a034d3a (opens in a new tab)
- git.kernel.org/stable/c/ccfe292a966079c61ea68a2da303b2a336170993 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8727-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8800-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-2 (opens in a new tab)