{"id":"CVE-2026-63868","title":"net: garp: fix unsigned integer underflow in garp_pdu_parse_attr","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: garp: fix unsigned integer underflow in garp_pdu_parse_attr\n\nThe receive-side GARP attribute parser computes dlen with reversed\noperands:\n\n        dlen = sizeof(*g…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= eca9ebac651f774d8b10fce7c5d173c3c3d3394f < 29f28172afb2ae7b31e9bf3e978396f20b381688","Linux >= eca9ebac651f774d8b10fce7c5d173c3c3d3394f < 973cf7c433d27f4d9556d0b7c332543be7ed7a6e","Linux >= eca9ebac651f774d8b10fce7c5d173c3c3d3394f < d8dcd14aa886b8effd83022c550669f4f262854b","Linux >= eca9ebac651f774d8b10fce7c5d173c3c3d3394f < 74e02121be1dcc0efcd56ebdf0171d6129105659","Linux >= eca9ebac651f774d8b10fce7c5d173c3c3d3394f < d4c86ea09ae3e63ee5aa86e941fcc38e0e39874a","Linux >= eca9ebac651f774d8b10fce7c5d173c3c3d3394f < 04e22fefac1af3e32f245e9045382348773b5d59","Linux >= eca9ebac651f774d8b10fce7c5d173c3c3d3394f < a11f1a671b1361f0f1278dc0041374f2730df73f","Linux >= eca9ebac651f774d8b10fce7c5d173c3c3d3394f < 16e408e607a94b646fb14a2a98422c6877ae4b3c","Linux 2.6.27"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-11-06T16:29:13.686506Z"},"published":"2026-07-19","updated":"2026-11-06","sourceUpdated":"2026-11-06T16:34:24.757Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-63868","references":[{"url":"https://git.kernel.org/stable/c/29f28172afb2ae7b31e9bf3e978396f20b381688"},{"url":"https://git.kernel.org/stable/c/973cf7c433d27f4d9556d0b7c332543be7ed7a6e"},{"url":"https://git.kernel.org/stable/c/d8dcd14aa886b8effd83022c550669f4f262854b"},{"url":"https://git.kernel.org/stable/c/74e02121be1dcc0efcd56ebdf0171d6129105659"},{"url":"https://git.kernel.org/stable/c/d4c86ea09ae3e63ee5aa86e941fcc38e0e39874a"},{"url":"https://git.kernel.org/stable/c/04e22fefac1af3e32f245e9045382348773b5d59"},{"url":"https://git.kernel.org/stable/c/a11f1a671b1361f0f1278dc0041374f2730df73f"},{"url":"https://git.kernel.org/stable/c/16e408e607a94b646fb14a2a98422c6877ae4b3c"}],"tags":["cve.org"],"epss":0.00121,"epssPercentile":0.01924,"ingestedAt":"2026-11-06T16:57:43.241Z","slug":"CVE-2026-63868","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet: garp: fix unsigned integer underflow in garp_pdu_parse_attr\n\nThe receive-side GARP attribute parser computes dlen with reversed\noperands:\n\n        dlen = sizeof(*ga) - ga->len;\n\nga->len is the on-wire attribute length and includes the GARP attribute\nheader. For normal attributes with data, ga->len is larger than\nsizeof(*ga), so the subtraction underflows in unsigned arithmetic.\n\nThe resulting value is later passed to garp_attr_lookup(), whose length\nargument is u8. After truncation, the parsed data length usually no\nlonger matches the length stored for locally registered attributes, so\nreceived Join/Leave events are ignored. This breaks the GARP receive path\nfor common attributes, such as GVRP VLAN registration attributes.\n\nCompute the data length as the attribute length minus the header length.\n\n## Affected\n\n- `Linux >= eca9ebac651f774d8b10fce7c5d173c3c3d3394f < 29f28172afb2ae7b31e9bf3e978396f20b381688`\n- `Linux >= eca9ebac651f774d8b10fce7c5d173c3c3d3394f < 973cf7c433d27f4d9556d0b7c332543be7ed7a6e`\n- `Linux >= eca9ebac651f774d8b10fce7c5d173c3c3d3394f < d8dcd14aa886b8effd83022c550669f4f262854b`\n- `Linux >= eca9ebac651f774d8b10fce7c5d173c3c3d3394f < 74e02121be1dcc0efcd56ebdf0171d6129105659`\n- `Linux >= eca9ebac651f774d8b10fce7c5d173c3c3d3394f < d4c86ea09ae3e63ee5aa86e941fcc38e0e39874a`\n- `Linux >= eca9ebac651f774d8b10fce7c5d173c3c3d3394f < 04e22fefac1af3e32f245e9045382348773b5d59`\n- `Linux >= eca9ebac651f774d8b10fce7c5d173c3c3d3394f < a11f1a671b1361f0f1278dc0041374f2730df73f`\n- `Linux >= eca9ebac651f774d8b10fce7c5d173c3c3d3394f < 16e408e607a94b646fb14a2a98422c6877ae4b3c`\n- `Linux 2.6.27`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}