{
  "cveId": "CVE-2026-99041",
  "url": "https://patchblox.com/security/cve/CVE-2026-99041",
  "summary": "CVE-2026-99041 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-99041, released October 24, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "ip6_gre: remove obsolete ERSPAN PMTU update",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  ip6_gre: remove obsolete ERSPAN PMTU update  A tc tunnel_key action can attach a METADATA_IP_TUNNEL dst to an skb, and mirred can redirect it to a native ip6erspan device. The legacy PMTU update in ip6erspan_tunnel_xmit() treats that metadata dst as a route. Since it has no output device, dst_dev(dst)-\u003Emtu dereferences NULL.  On v7.2 with KASAN, an initial UID/GID 65534 process with CapEff 0 used self-created user and network namespaces to trigger:    KASAN: null-ptr-deref   RIP: ip6erspan_tunnel_xmit\u002B0x10fc/0x2cc0   Kernel panic - not syncing: Fatal exception in interrupt  The update is obsolete. Commit fe1a4ca0a2b7 (\u0022ip6_gre: process toobig in a better way\u0022) changed IPv6 GRE Too Big handling to update the underlay route and removed the equivalent block from __gre6_xmit(). ip6_tnl_xmit() then propagates the underlay PMTU to the overlay route.  Remove the stale ERSPAN copy and its now-unused dst variable. This eliminates the metadata-dst dereference and keeps ERSPAN aligned with IPv6 GRE PMTU handling.",
  "published": "2026-10-23T13:17:27Z",
  "severity": "Moderate",
  "cvss": 5.5,
  "epss": 0.00173,
  "epssPercentile": 0.06791,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-99041",
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.12.115-2",
      "fix": "DEBIAN-CVE-2026-99041",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-99041",
      "released": "2026-10-24T13:25:57Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.11-1",
      "fix": "DEBIAN-CVE-2026-99041",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-99041",
      "released": "2026-10-24T13:25:57Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T19:12:23Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}