{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:12",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:13",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "In the Linux kernel, the following vulnerability has been resolved:  mpls: reload header after pskb_may_pull()  mpls_select_multipath() calls mpls_multipath_hash() to choose a nexthop when an MPLS route has multiple nexthops.  While walking the MPLS label stack, the hash routine caches hdr for the current label.  After finding the bottom-of-stack label, it calls pskb_may_pull() before reading the inner IP header.  If an skb is constructed with the inner IP header in nonlinear data and insufficient tailroom in the linear head, pskb_may_pull() calls pskb_expand_head() to replace the skb head and free the old one.  This leaves hdr pointing to freed memory.  The IPv6 path can invalidate hdr again when it performs a second pull for the larger header.  The issue was found through static analysis.  A reproducer sending a legal Geneve packet through a bareudp/MPLS multipath setup triggered the same KASAN report in 2 of 2 unpatched runs:    BUG: KASAN: slab-use-after-free in mpls_select_multipath   Read of size 1 at addr ffff88800ecc6e20 by task ksoftirqd/1/23    Call Trace:    mpls_select_multipath    mpls_forward    __netif_receive_skb_list_core    netif_receive_skb_list_internal    napi_complete_done    gro_cell_poll    __napi_poll    net_rx_action    Freed by task 23:    kfree    pskb_expand_head    __pskb_pull_tail    mpls_select_multipath  Reload hdr from the current skb head after each successful pull before deriving the inner IPv4 or IPv6 header pointer.",
  "id": "DEBIAN-CVE-2026-89555",
  "modified": "2026-09-15T08:47:49.890469119Z",
  "published": "2026-09-11T20:19:39.147Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-89555"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "upstream": [
    "CVE-2026-89555"
  ]
}