{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "8610c7c6e3bd647ff98d21c8bc0580e77bc2f8b3"
            },
            {
              "fixed": "bde199c72d319a4e207f88daabc888317504e2fb"
            },
            {
              "fixed": "be1fa0aa9b4fdd5a8b7a61ba520a690a68391e6e"
            },
            {
              "fixed": "0a9e8053f1f8a8e1bfc1dd61ffe67be6c1180402"
            },
            {
              "fixed": "8e8be63465a5e80394c70324603dfea1bfdad48f"
            },
            {
              "fixed": "4babc2d9fda2df43823b85d08a0180b68f1b0854"
            },
            {
              "fixed": "c261d07a80576dc8ccf394ef8f074f8c67a06b37"
            },
            {
              "fixed": "7398ebefbfd4f8a31d4f665a4213302fa995494b"
            },
            {
              "fixed": "9e6bf146b55999a095bb14f73a843942456d1adc"
            }
          ],
          "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": "5.10.258"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.209"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.175"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.140"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.86"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.27"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.0.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43501.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: rpl: reserve mac_len headroom when recompressed SRH grows\n\nipv6_rpl_srh_rcv() decompresses an RFC 6554 Source Routing Header, swaps\nthe next segment into ipv6_hdr-\u003edaddr, recompresses, then pulls the old\nheader and pushes the new one plus the IPv6 header back.  The\nrecompressed header can be larger than the received one when the swap\nreduces the common-prefix length the segments share with daddr (CmprI=0,\nCmprE\u003e0, seg[0][0] != daddr[0] gives the maximum +8 bytes).\n\npskb_expand_head() was gated on segments_left == 0, so on earlier\nsegments the push consumed unchecked headroom.  Once skb_push() leaves\nfewer than skb-\u003emac_len bytes in front of data,\nskb_mac_header_rebuild()'s call to:\n\n\tskb_set_mac_header(skb, -skb-\u003emac_len);\n\nwill store (data - head) - mac_len into the u16 mac_header field, which\nwraps to ~65530, and the following memmove() writes mac_len bytes ~64KiB\npast skb-\u003ehead.\n\nA single AF_INET6/SOCK_RAW/IPV6_HDRINCL packet over lo with a two\nsegment type-3 SRH (CmprI=0, CmprE=15) reaches headroom 8 after one\npass; KASAN reports a 14-byte OOB write in ipv6_rthdr_rcv.\n\nFix this by expanding the head whenever the remaining room is less than\nthe push size plus mac_len, and request that much extra so the rebuilt\nMAC header fits afterwards.",
  "id": "CVE-2026-43501",
  "modified": "2026-07-08T05:38:19.135855121Z",
  "published": "2026-05-21T12:17:49.885Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0a9e8053f1f8a8e1bfc1dd61ffe67be6c1180402"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4babc2d9fda2df43823b85d08a0180b68f1b0854"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7398ebefbfd4f8a31d4f665a4213302fa995494b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8e8be63465a5e80394c70324603dfea1bfdad48f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9e6bf146b55999a095bb14f73a843942456d1adc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bde199c72d319a4e207f88daabc888317504e2fb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/be1fa0aa9b4fdd5a8b7a61ba520a690a68391e6e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c261d07a80576dc8ccf394ef8f074f8c67a06b37"
    },
    {
      "type": "WEB",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-43501.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:25191"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:25217"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:27713"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:27731"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:33900"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:34094"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:34095"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/security/cve/CVE-2026-43501"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43501.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43501"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2480457"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.7.5",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "ipv6: rpl: reserve mac_len headroom when recompressed SRH grows"
}