{
  "cveId": "CVE-2026-89720",
  "url": "https://patchblox.com/security/cve/CVE-2026-89720",
  "summary": "CVE-2026-89720 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-89720, released September 23, 2026. It is not reported as exploited. Patch Radar priority: High.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  ubifs: fix out-of-bounds read in signature lengt...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  ubifs: fix out-of-bounds read in signature length check  ubifs_sb_verify_signature() bounds the on-disk ubifs_sig_node-\u003Elen field before handing the signature payload to verify_pkcs7_signature(), but the check has the wrong sign:  \tif (le32_to_cpu(signode-\u003Elen) \u003E snod-\u003Elen \u002B sizeof(struct ubifs_sig_node))  The signature bytes start sizeof(struct ubifs_sig_node) (UBIFS_SIG_NODE_SZ, 64 bytes) into the node, so the payload is at most  \tsnod-\u003Elen - sizeof(struct ubifs_sig_node)  bytes long. Adding the header size instead of subtracting it accepts a declared length up to 2 * UBIFS_SIG_NODE_SZ larger than the node actually holds -- past the end of c-\u003Esbuf, which is vmalloc(c-\u003Eleb_size). verify_pkcs7_signature() -\u003E pkcs7_parse_message() -\u003E asn1_ber_decoder() is then handed that inflated length and reads beyond the allocation while walking the DER headers. The node length comes straight from the mounted image, so a crafted signed UBIFS image reaches this via ubifs_read_superblock() before the signature is cryptographically checked.  snod-\u003Elen is guaranteed to be \u003E= UBIFS_SIG_NODE_SZ by the node scanner (c-\u003Eranges[UBIFS_SIG_NODE].min_len == UBIFS_SIG_NODE_SZ), so the corrected subtraction cannot underflow. Legitimately signed images are unaffected: a correct superblock never declares a signature longer than the node it is embedded in.",
  "published": "2026-09-11T20:20:00Z",
  "severity": "high",
  "cvss": 7.7,
  "cvssVector": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
  "epss": 0.00185,
  "epssPercentile": 0.08144,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "6.1.190-1",
      "fix": "DEBIAN-CVE-2026-89720",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-89720",
      "released": "2026-09-23T19:19:02Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.12.111-1",
      "fix": "DEBIAN-CVE-2026-89720",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-89720",
      "released": "2026-09-23T19:19:02Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.6-1",
      "fix": "DEBIAN-CVE-2026-89720",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-89720",
      "released": "2026-09-23T19:19:02Z"
    },
    {
      "platform": "linux",
      "product": "linux-6.12",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "6.12.111-1~deb12u1",
      "fix": "DEBIAN-CVE-2026-89720",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-89720",
      "released": "2026-09-23T19:19:02Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T00:53:09Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}