CVE-2026-53238: netlabel: validate unlabeled address and mask attribute lengths
In the Linux kernel, the following vulnerability has been resolved:
netlabel: validate unlabeled address and mask attribute lengths
netlblunlabeladdrinfoget() used the address attribute length to determine whether the attribute data could be read as an IPv4 or IPv6 address, but did not independently validate the corresponding mask attribute length. A crafted Generic Netlink request could therefore provide a valid IPv4/IPv6 address attribute with a shorter mask attribute, which would later be read as a full struct inaddr or struct in6addr.
NLABINARY policy lengths are maximum lengths by default, so use NLAPOLICYEXACTLEN() for the unlabeled IPv4/IPv6 address and mask attributes. This rejects short attributes during policy validation and also exposes the exact length requirements through policy introspection.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 6.6.143.1-1 - Configuration
Update netlabel code to validate unlabeled address and mask attribute lengths using NLA_POLICY_EXACT_LEN() (instead of relying on maximum-length default behavior), so short attributes are rejected during policy validation and exact length requirements are enforced.
Linux kernel netlabel NLA policy validation for unlabeled IPv4/IPv6 address/mask attributes = Use NLA_POLICY_EXACT_LEN() for unlabeled IPv4/IPv6 address and mask (reject short attributes)
Event History
Frequently Asked Questions
What is the severity of CVE-2026-53238?
CVE-2026-53238 has a risk rating of 37, indicating a moderate level of severity.
What causes CVE-2026-53238?
CVE-2026-53238 is caused by inadequate validation of unlabeled address and mask attribute lengths in the Linux kernel.
How do I fix CVE-2026-53238?
To fix CVE-2026-53238, update your Linux kernel to the latest patched version that addresses this vulnerability.
What is the impact of CVE-2026-53238?
The impact of CVE-2026-53238 includes potential security risks due to improper handling of address and mask attributes.
Is CVE-2026-53238 related to network security?
Yes, CVE-2026-53238 is related to network security as it affects how the Linux kernel manages address labeling for network operations.