{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "9f427a0e474a67b454420c131709600d44850486"
            },
            {
              "fixed": "aa4fe0b450a461aa1162fe8375f5d28f4c957df8"
            },
            {
              "fixed": "b1c0783b2facc398437ad8f8b86c636d7a78f8db"
            },
            {
              "fixed": "bfaaff99238326166694354a63a76c02563f98b1"
            },
            {
              "fixed": "d9640239827d6d0cb84263b590f7a4f1596c17eb"
            },
            {
              "fixed": "fed638a248116b8a249bd4202d28e5934bdc65ad"
            },
            {
              "fixed": "d82b90a38c2ca8a0694428eab0e9551c23f2447d"
            },
            {
              "fixed": "49d38c1b4390412f8950d33dfaee0ccbd17beb81"
            },
            {
              "fixed": "29e63b8d9fc150cc191b1c6eb7e16e1247e1b650"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "ad864d9fce0ec56cc8f6afe5c6a0e6d7f484b9eb"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "4.9.8"
            },
            {
              "fixed": "4.10"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.10.0"
            },
            {
              "fixed": "5.10.270"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.221"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.188"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.157"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.109"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.50"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89555.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmpls: reload header after pskb_may_pull()\n\nmpls_select_multipath() calls mpls_multipath_hash() to choose a nexthop\nwhen an MPLS route has multiple nexthops.  While walking the MPLS label\nstack, the hash routine caches hdr for the current label.  After finding\nthe bottom-of-stack label, it calls pskb_may_pull() before reading the\ninner IP header.\n\nIf an skb is constructed with the inner IP header in nonlinear data and\ninsufficient tailroom in the linear head, pskb_may_pull() calls\npskb_expand_head() to replace the skb head and free the old one.  This\nleaves hdr pointing to freed memory.  The IPv6 path can invalidate hdr\nagain when it performs a second pull for the larger header.\n\nThe issue was found through static analysis.  A reproducer sending a legal\nGeneve packet through a bareudp/MPLS multipath setup triggered the same\nKASAN report in 2 of 2 unpatched runs:\n\n  BUG: KASAN: slab-use-after-free in mpls_select_multipath\n  Read of size 1 at addr ffff88800ecc6e20 by task ksoftirqd/1/23\n\n  Call Trace:\n   mpls_select_multipath\n   mpls_forward\n   __netif_receive_skb_list_core\n   netif_receive_skb_list_internal\n   napi_complete_done\n   gro_cell_poll\n   __napi_poll\n   net_rx_action\n\n  Freed by task 23:\n   kfree\n   pskb_expand_head\n   __pskb_pull_tail\n   mpls_select_multipath\n\nReload hdr from the current skb head after each successful pull before\nderiving the inner IPv4 or IPv6 header pointer.",
  "id": "CVE-2026-89555",
  "modified": "2026-09-15T03:31:05.268234928Z",
  "published": "2026-09-11T19:44:28.331Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/29e63b8d9fc150cc191b1c6eb7e16e1247e1b650"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/49d38c1b4390412f8950d33dfaee0ccbd17beb81"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/aa4fe0b450a461aa1162fe8375f5d28f4c957df8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b1c0783b2facc398437ad8f8b86c636d7a78f8db"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bfaaff99238326166694354a63a76c02563f98b1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d82b90a38c2ca8a0694428eab0e9551c23f2447d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d9640239827d6d0cb84263b590f7a4f1596c17eb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fed638a248116b8a249bd4202d28e5934bdc65ad"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89555.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89555"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "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": "mpls: reload header after pskb_may_pull()"
}