Bug 2492828 (CVE-2026-53238)

Summary: CVE-2026-53238 kernel: netlabel: validate unlabeled address and mask attribute lengths
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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OS: Linux   
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Description OSIDB Bzimport 2026-06-25 10:07:54 UTC 
In the Linux kernel, the following vulnerability has been resolved:

netlabel: validate unlabeled address and mask attribute lengths

netlbl_unlabel_addrinfo_get() 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 in_addr or
struct in6_addr.

NLA_BINARY policy lengths are maximum lengths by default, so use
NLA_POLICY_EXACT_LEN() 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.
Comment 1 Mauro Matteo Cascella 2026-06-29 14:27:52 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062510-CVE-2026-53238-06fb@gregkh/T