EUVD-2026-39329
GHSA-5qwx-4q7j-hwm2
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Local Netlink interface requires low privilege; availability-only impact confirmed by description; no confidentiality or integrity impact substantiated by vendor scoring.
Primary rating from NVD.
CVSS VectorNVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
5DescriptionNVD
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.
AnalysisAI
Out-of-bounds read in the Linux kernel netlabel subsystem allows a local low-privileged attacker to crash the kernel by submitting a crafted Generic Netlink request with a valid IPv4/IPv6 address attribute paired with a shorter-than-expected mask attribute. The netlbl_unlabel_addrinfo_get() function relied solely on the address attribute length to determine address family, then unconditionally read the mask attribute as a full struct in_addr (4 bytes) or struct in6_addr (16 bytes) without independently validating the mask length. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires local access to the target system and the CAP_NET_ADMIN capability, which is held by root or - on kernels with unprivileged user namespaces enabled (the default on many distributions including Ubuntu) - by any unprivileged user who creates a user namespace. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 vector (AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) scores this as a local, low-complexity availability impact. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | A local user on a Linux system with user namespaces enabled creates a user namespace, obtains CAP_NET_ADMIN within it, and sends a crafted GENL_NETLBL_UNLABEL Netlink message containing a valid 4-byte IPv4 address attribute but a 1-byte mask attribute. The kernel's netlbl_unlabel_addrinfo_get() reads 4 bytes for the mask by casting the 1-byte attribute buffer to struct in_addr, reading 3 bytes of adjacent kernel memory and potentially causing a kernel panic or memory corruption. … |
| Remediation | Upgrade to a patched kernel version: 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, 6.18.36, 7.0.13, or 7.1 as appropriate for the deployed branch. … Detailed patch versions, workarounds, and compensating controls in full report. |
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