CVE-2026-63868
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.
Affected versions
Linux kernel versions
2.6.27
and later are affected. Fixed in
5.10.259,
5.15.210,
6.1.176,
6.6.143,
6.12.94,
6.18.36,
7.0.13,
7.1
and their respective stable series.
References
8 totalFrequently asked questions
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What is CVE-2026-63868?
CVE-2026-63868 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 2.6.27 onward and has been patched in 5.10.259, 5.15.210, 6.1.176 and others. CVE-2026-63868 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-63868?
Yes — CVE-2026-63868 has been patched. Fixed versions include 5.10.259, 5.15.210, 6.1.176 and others. If you are running Linux kernel 2.6.27 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-63868 actively exploited?
No — CVE-2026-63868 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.