ubuntu-cve-2026-55555
Vulnerability from osv_ubuntu
Published
2026-07-30 00:00
Modified
2026-07-30 00:00
Summary
Details

Dompdf is an HTML to PDF converter for PHP. Versions 3.15 and prior are vulnerable to a File Existence Oracle attack through the manipulation of the CSS @font-face directive. By providing malicious HTML that references local files via the file:// protocol repeatedly, an attacker can trigger PHP memory exhaustion. Because Dompdf behaves differently depending on whether a referenced local file exists (an existing file is processed repeatedly until it triggers an "Allowed memory size exhausted" crash, whereas a missing file fails fast or is ignored and never hits the memory limit), an attacker can use this observable discrepancy as an oracle to enumerate sensitive files on the server regardless of CHROOT restrictions. Exploitation requires the attacker to supply unrestricted or unsanitized HTML in a request that permits large data, plus a configuration where Dompdf's memory limit is low enough to be exhausted (with  $_dompdf_show_warnings=true  making the overflow easier to reach). This issue has been fixed in version 3.16.

Severity
2.3 (Low)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "php-dompdf",
            "binary_version": "0.6.1+dfsg-2ubuntu1+esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "php-dompdf",
        "purl": "pkg:deb/ubuntu/php-dompdf@0.6.1+dfsg-2ubuntu1+esm1?arch=source\u0026distro=esm-apps/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.6.1+dfsg-2",
        "0.6.1+dfsg-2build1",
        "0.6.1+dfsg-2ubuntu1",
        "0.6.1+dfsg-2ubuntu1+esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "php-dompdf",
            "binary_version": "0.6.2+dfsg-3ubuntu0.18.04.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "php-dompdf",
        "purl": "pkg:deb/ubuntu/php-dompdf@0.6.2+dfsg-3ubuntu0.18.04.1~esm1?arch=source\u0026distro=esm-apps/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.6.2+dfsg-3",
        "0.6.2+dfsg-3ubuntu0.18.04.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "php-dompdf",
            "binary_version": "0.6.2+dfsg-3ubuntu0.20.04.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "php-dompdf",
        "purl": "pkg:deb/ubuntu/php-dompdf@0.6.2+dfsg-3ubuntu0.20.04.1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.6.2+dfsg-3",
        "0.6.2+dfsg-3ubuntu0.20.04.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "php-dompdf",
            "binary_version": "0.6.2+dfsg-3.1ubuntu0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "php-dompdf",
        "purl": "pkg:deb/ubuntu/php-dompdf@0.6.2+dfsg-3.1ubuntu0.1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.6.2+dfsg-3.1",
        "0.6.2+dfsg-3.1ubuntu0.1"
      ]
    }
  ],
  "aliases": [],
  "details": "Dompdf is an HTML to PDF converter for PHP. Versions 3.15 and prior are vulnerable to a File Existence Oracle attack through the manipulation of the CSS @font-face directive. By providing malicious HTML that references local files via the file:// protocol repeatedly, an attacker can trigger PHP memory exhaustion. Because Dompdf behaves differently depending on whether a referenced local file exists (an existing file is processed repeatedly until it triggers an \"Allowed memory size exhausted\" crash, whereas a missing file fails fast or is ignored and never hits the memory limit), an attacker can use this observable discrepancy as an oracle to enumerate sensitive files on the server regardless of CHROOT restrictions. Exploitation requires the attacker to supply unrestricted or unsanitized HTML in a request that permits large data, plus a configuration where Dompdf\u0027s memory limit is low enough to be exhausted (with \u00a0$_dompdf_show_warnings=true\u00a0 making the overflow easier to reach). This issue has been fixed in version 3.16.",
  "id": "UBUNTU-CVE-2026-55555",
  "modified": "2026-07-30T00:00:00Z",
  "published": "2026-07-30T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-55555"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-55555"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/dompdf/dompdf/security/advisories/GHSA-7x2p-4jvh-6384"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/dompdf/dompdf/commit/75c39a083bf7298044fb27399b4cc183054438b4"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/dompdf/dompdf/releases/tag/v3.1.6"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-55555"
  ]
}



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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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