{
  "cveId": "CVE-2026-61626",
  "url": "https://patchblox.com/security/cve/CVE-2026-61626",
  "summary": "CVE-2026-61626 is fixed in 2 products on 1 platform, first by libass9 1:0.17.4-2ubuntu0.1~esm1, released July 13, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "libass: libass is a portable subtitle renderer for the ASS/SSA (Advanced Substation Alpha/Substation Alpha) subtitle format",
  "description": "libass is a portable subtitle renderer for the ASS/SSA (Advanced Substation Alpha/Substation Alpha) subtitle format. From 0.17.4 until 0.17.5, libass event pruning does not guard negative Matroska \u0060ReadOrder\u0060 values, allowing an attacker to clear arbitrarily many bits to zero at attacker-controlled positions near the NULL pointer. Exploitation requires a malicious Matroska stream loaded through \u0060ass_process_chunk\u0060, enabled read-order checking, and later pruning of the malicious events. Read-order checking is enabled by default unless \u0060ass_set_check_readorder\u0060 is called with zero; pruning must occur explicitly through \u0060ass_prune_events\u0060 or through automatic pruning previously enabled with \u0060ass_configure_prune\u0060. On common systems with arithmetic right shift, 32-bit int values, the upper address region reserved to the kernel, and matching binary/kernel architecture, the expected consequence is denial of service. More extensive exploitation on uncommon systems is theoretical and strongly constrained by the target addresses, bit-clearing-only mutation, and ASLR. This issue is fixed in version 0.17.5.",
  "published": "2026-07-13T17:00:00Z",
  "severity": "Medium",
  "epss": 0.00118,
  "epssPercentile": 0.0174,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "libass",
      "release": "Debian 14",
      "fixedVersion": "1:0.17.5-1",
      "fix": "DEBIAN-CVE-2026-61626",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-61626",
      "released": "2026-07-14T16:28:19Z"
    },
    {
      "platform": "linux",
      "product": "libass9",
      "release": "Ubuntu 26.04.1 LTS (resolute)",
      "fixedVersion": "1:0.17.4-2ubuntu0.1~esm1",
      "fix": "libass9 1:0.17.4-2ubuntu0.1~esm1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-resolute-libass9-1-0.17.4-2ubuntu0.1-esm1",
      "released": "2026-07-13T17:00:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T13:06:02Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}