cve-2026-55555

LOW CVSS 2.3 cvelistv5
Description

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.

Timeline
Published
2026-07-28 19:23 UTC
Last Modified
2026-07-28
CVSS Details
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
Affected Products
  • dompdf dompdf
Weaknesses (CWE)
CWE-203
SSVC (CISA Stakeholder-Specific Vulnerability Categorization) CISA Coordinator v2.0.3
Exploitation
poc
Automatable
no
Technical Impact
partial
Decision timestamp
2026-07-28T19:43:22.142480Z

What is SSVC? — CISA's vulnerability-prioritisation framework using a decision tree rather than a single score.

References
Linked Vulnerabilities

No linked vulnerabilities found.

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-55555",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-28T19:43:22.142480Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-28T19:43:31.156Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/dompdf/dompdf/security/advisories/GHSA-7x2p-4jvh-6384"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "dompdf",
          "vendor": "dompdf",
          "versions": [
            {
              "status": "affected",
              "version": "< 3.1.6"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 2.3,
            "baseSeverity": "LOW",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "PASSIVE",
            "vectorString": "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",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "LOW",
            "vulnIntegrityImpact": "NONE"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-203",
              "description": "CWE-203: Observable Discrepancy",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-28T19:23:45.525Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/dompdf/dompdf/security/advisories/GHSA-7x2p-4jvh-6384",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/dompdf/dompdf/security/advisories/GHSA-7x2p-4jvh-6384"
        },
        {
          "name": "https://github.com/dompdf/dompdf/commit/75c39a083bf7298044fb27399b4cc183054438b4",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/dompdf/dompdf/commit/75c39a083bf7298044fb27399b4cc183054438b4"
        },
        {
          "name": "https://github.com/dompdf/dompdf/releases/tag/v3.1.6",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/dompdf/dompdf/releases/tag/v3.1.6"
        }
      ],
      "source": {
        "advisory": "GHSA-7x2p-4jvh-6384",
        "discovery": "UNKNOWN"
      },
      "title": "Dompdf: File existence oracle via font-face stylesheet declaration"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-55555",
    "datePublished": "2026-07-28T19:23:45.525Z",
    "dateReserved": "2026-06-16T23:11:20.213Z",
    "dateUpdated": "2026-07-28T19:43:31.156Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}
View JSON API Download JSON