{"id":"CVE-2026-63868","summary":"net: garp: fix unsigned integer underflow in garp_pdu_parse_attr","details":"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(*ga) - ga-\u003elen;\n\nga-\u003elen is the on-wire attribute length and includes the GARP attribute\nheader. For normal attributes with data, ga-\u003elen 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.","modified":"2026-08-12T03:30:46.930959244Z","published":"2026-07-19T14:18:37.823Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63868.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/04e22fefac1af3e32f245e9045382348773b5d59"},{"type":"WEB","url":"https://git.kernel.org/stable/c/16e408e607a94b646fb14a2a98422c6877ae4b3c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/29f28172afb2ae7b31e9bf3e978396f20b381688"},{"type":"WEB","url":"https://git.kernel.org/stable/c/74e02121be1dcc0efcd56ebdf0171d6129105659"},{"type":"WEB","url":"https://git.kernel.org/stable/c/973cf7c433d27f4d9556d0b7c332543be7ed7a6e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a11f1a671b1361f0f1278dc0041374f2730df73f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d4c86ea09ae3e63ee5aa86e941fcc38e0e39874a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d8dcd14aa886b8effd83022c550669f4f262854b"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63868.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63868"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"eca9ebac651f774d8b10fce7c5d173c3c3d3394f"},{"fixed":"29f28172afb2ae7b31e9bf3e978396f20b381688"},{"fixed":"973cf7c433d27f4d9556d0b7c332543be7ed7a6e"},{"fixed":"d8dcd14aa886b8effd83022c550669f4f262854b"},{"fixed":"74e02121be1dcc0efcd56ebdf0171d6129105659"},{"fixed":"d4c86ea09ae3e63ee5aa86e941fcc38e0e39874a"},{"fixed":"04e22fefac1af3e32f245e9045382348773b5d59"},{"fixed":"a11f1a671b1361f0f1278dc0041374f2730df73f"},{"fixed":"16e408e607a94b646fb14a2a98422c6877ae4b3c"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-63868.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.27"},{"fixed":"5.10.259"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.210"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.176"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.143"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.94"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.36"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.13"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-63868.json"}}],"schema_version":"1.9.0"}