{"schema_version":"1.9.0","id":"CVE-2026-63925","published":"2026-07-19T14:55:26.442Z","modified":"2026-08-12T03:51:10.405025964Z","summary":"macsec: fix replay protection at XPN lower-PN wrap","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nmacsec: fix replay protection at XPN lower-PN wrap\n\nIn macsec_post_decrypt(), when pn is U32_MAX, pn + 1 overflows u32 to 0\nand the first branch never fires. If next_pn_halves.lower is also in the\nupper half, pn_same_half(pn, lower) is true and the XPN else-if does not\nfire either, leaving next_pn_halves unchanged. An attacker that captures\nthe legitimate frame carrying pn == 0xFFFFFFFF on an XPN association\ncan then replay it indefinitely, since lowest_pn never rises above\nthe captured pn and macsec_decrypt() reconstructs the same IV.\n\nExtend the XPN else-if to also fire when pn + 1 wraps to 0, so receipt\nof pn == U32_MAX advances next_pn_halves to (upper + 1, 0).","affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"a21ecf0e033807b976967286e6c392f48ee2049f"},{"fixed":"dd7306779c6ce1238f4cdc34f3c1f2246b854457"},{"fixed":"d15130461df388136b62a7b0ce9f66e7e2fa9ff1"},{"fixed":"23c0e230eab397d7f68be2538790ac41d3bb91fd"},{"fixed":"679e13a65e68a67c8b3c0467c02ee89157ec6f0f"},{"fixed":"79495a1b0944fe31ffd54b54b00211b493590d62"},{"fixed":"6d00f5c7e5ff7ec4795b7f5f8ed88bd346641652"},{"fixed":"d55acbe577db892b60547b6ef1c020b359331a6d"},{"fixed":"e68842b3356471ba56c882209f324613dac47f64"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63925.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.7.0"},{"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":"6.12.93"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.35"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.12"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63925.json"}}],"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/23c0e230eab397d7f68be2538790ac41d3bb91fd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/679e13a65e68a67c8b3c0467c02ee89157ec6f0f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6d00f5c7e5ff7ec4795b7f5f8ed88bd346641652"},{"type":"WEB","url":"https://git.kernel.org/stable/c/79495a1b0944fe31ffd54b54b00211b493590d62"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d15130461df388136b62a7b0ce9f66e7e2fa9ff1"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d55acbe577db892b60547b6ef1c020b359331a6d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/dd7306779c6ce1238f4cdc34f3c1f2246b854457"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e68842b3356471ba56c882209f324613dac47f64"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63925.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63925"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63925.json"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H"}]}