{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "a21ecf0e033807b976967286e6c392f48ee2049f"
            },
            {
              "fixed": "dd7306779c6ce1238f4cdc34f3c1f2246b854457"
            },
            {
              "fixed": "d15130461df388136b62a7b0ce9f66e7e2fa9ff1"
            },
            {
              "fixed": "23c0e230eab397d7f68be2538790ac41d3bb91fd"
            },
            {
              "fixed": "679e13a65e68a67c8b3c0467c02ee89157ec6f0f"
            },
            {
              "fixed": "79495a1b0944fe31ffd54b54b00211b493590d62"
            },
            {
              "fixed": "6d00f5c7e5ff7ec4795b7f5f8ed88bd346641652"
            },
            {
              "fixed": "d55acbe577db892b60547b6ef1c020b359331a6d"
            },
            {
              "fixed": "e68842b3356471ba56c882209f324613dac47f64"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "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"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63925.json"
  },
  "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).",
  "id": "CVE-2026-63925",
  "modified": "2026-07-22T05:29:44.437359438Z",
  "published": "2026-07-19T14:55:26.442Z",
  "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"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "macsec: fix replay protection at XPN lower-PN wrap"
}