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NVD / CVE Program· CNA GitHub_M

CVE-2026-55555: Dompdf: File existence oracle via font-face stylesheet declaration

Noroxi assessment

Priority: Monitor (action score 9/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.50% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No special conditions are required; it is repeatable.
  • Fixed version: dompdf dompdf 3.16.

Low priority for now. Upgrade to dompdf dompdf 3.16 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

LowCVSS 2.3 · v4.0—No exploit Fix available
Published
Jul 28, 2026
Updated
Aug 5, 2026
EPSS
0.5% · 43th percentile

Report tools

JSON

Action score

9

Monitor

Low priority for now.

CVSS
9 / 40 · 2.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
2.3
NVD has not scored this yet; the score shown is the CNA’s.

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-55555

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
dompdf projectdompdf

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • dompdf project dompdfbefore 3.16

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • dompdf dompdf

    • < 3.1.6affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12php-dompdffrom 0—
Packagistdompdf/dompdfbefore 3.1.63.1.6

Same product

dompdf project: all records

Other highest-scoring records for the same primary product.

  • CVE-2022-28368Dompdf 1.2.1 allows remote code execution via a .php file in the src:url field of an @font-face Cascading Style Sheets (CSS) statement (with
    64This week
  • CVE-2023-24813URI validation failure on SVG parsing. Bypass of CVE-2023-23924
    40Plan
  • CVE-2023-23924URI validation failure on SVG parsing in Dompdf
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2021-3902Nov 15, 2024 · Improper Restriction of XML External Entity Reference in dompdf/dompdf
    39Monitor
  • ← EarlierCVE-2026-55554Jul 28, 2026 · Dompdf: Chroot Validation Bypass
    9Monitor
  • Later →CVE-2026-56722Jul 28, 2026 · Dompdf: Local file read due to improper file path validation in SVG images encoded as data-URI
    25Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
dompdf dompdf3.16 · descriptionVendor (CNA)
Packagist:dompdf/dompdf3.1.6Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
P
Scope
X

Weakness class (CWE)

CWE-203 · Observable Discrepancy

CVSS vector

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records