CVE Catalog

CVE-2026-89776

Low risk· EPSS 10%
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.21%

10th percentile - higher than 10% of all known CVEs

Summary

In the Linux kernel's vxlan vnifilter, the GROUP/GROUP6 attribute policy uses NLA_BINARY with only a maximum length, allowing payloads shorter than the address size. The consumer reads the attribute as an unconditional 4-byte load, over-reading up to 3 bytes of uninitialised slab data and disclosing kernel memory via RTM_GETTUNNEL.

Risk Assessment

An attacker able to create VXLAN tunnels can read uninitialised kernel memory, potentially disclosing sensitive information and aiding further attacks.

Recommendation

Update the Linux kernel to a version enforcing exact lengths for GROUP (4 bytes) and GROUP6 (16 bytes) attributes. Until then, restrict VXLAN interface configuration to trusted users.

Related vulnerabilities

Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: vxlan: vnifilter: enforce exact length of GROUP/GROUP6 attributes The VXLAN VNI filter entry policy declares the GROUP/GROUP6 address attributes as NLA_BINARY with only a maximum length, so validate_nla() accepts a payload shorter than the address. The GROUP consumer reads it with nla_get_in_addr(), an unconditional 4-byte load, so a short attribute over-reads up to 3 bytes of uninitialised slab data, which are stored into remote_ip and echoed back via RTM_GETTUNNEL, disclosing kernel memory. Switch both entries to NLA_POLICY_EXACT_LEN() so the validator rejects any GROUP/GROUP6 that is not exactly 4 / 16 bytes; a valid address is always sent at full width.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS