CVE Catalog

CVE-2026-63868

Low risk· EPSS 6%
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.17%

6th percentile - higher than 6% of all known CVEs

Summary

A vulnerability was found in the Linux kernel's GARP (Generic Attribute Registration Protocol) attribute parser. The bug is caused by reversed operands in data length calculation, leading to an unsigned integer underflow. As a result, received Join/Leave events are ignored, breaking protocols like GVRP.

Risk Assessment

The organization may experience issues with GVRP-based VLAN operations, as VLAN registration changes will not be processed correctly. This can lead to network misconfiguration, traffic isolation errors, or failures in services relying on dynamic VLAN management.

Recommendation

Immediately update the Linux kernel to a version containing the fix (commit that corrects the reversed operands in garp_pdu_parse_attr). A system reboot is required after the update.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: net: garp: fix unsigned integer underflow in garp_pdu_parse_attr The receive-side GARP attribute parser computes dlen with reversed operands: dlen = sizeof(*ga) - ga->len; ga->len is the on-wire attribute length and includes the GARP attribute header. For normal attributes with data, ga->len is larger than sizeof(*ga), so the subtraction underflows in unsigned arithmetic. The resulting value is later passed to garp_attr_lookup(), whose length argument is u8. After truncation, the parsed data length usually no longer matches the length stored for locally registered attributes, so received Join/Leave events are ignored. This breaks the GARP receive path for common attributes, such as GVRP VLAN registration attributes. Compute the data length as the attribute length minus the header length.

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