# CVE-2026-55554: Dompdf: Chroot Validation Bypass

> An attacker can bypass chroot restrictions in Dompdf to read sensitive files outside the allowed directory by exploiting a flawed path validation check.

- **Severity:** Low 2.3 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 28 Jul 2026
- **Updated:** 29 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-55554, GHSA-wvh6-f5jh-8gw4, UBUNTU-CVE-2026-55554

## What is CVE-2026-55554?

CVE-2026-55554 is a low-severity path traversal vulnerability in dompdf, published on 28 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Dompdf is an HTML to PDF converter for PHP. In versions 3.15 and prior, the validateLocalUri() method enforces chroot boundaries with a strpos() prefix check after normalizing paths with  realpath() . Because normalization strips the trailing directory separator from  $chrootPath , the check only verifies that  $chrootPath  is a string prefix of $realfile, so a chroot of  /var/www  also matches sibling directories like /var/www2 , /var/www-admin, or /var/www_backup. An attacker who controls part of the rendered HTML could exploit this to escape the chroot and read sensitive files outside the allowed directory. This issue has been fixed in version 3.16.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2026-55554?

2 open source packages ship an affected version, including dompdf/dompdf. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `dompdf/dompdf` | Packagist | All versions | 3.1.6 |
| `dompdf/dompdf` | Packagist | All versions | 3.1.6 |

Products: Dompdf Project Dompdf.

## How do I fix CVE-2026-55554?

Upgrade dompdf/dompdf to 3.1.6 or later.

## Is CVE-2026-55554 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55554 exists.

## Other vulnerabilities in dompdf

- [CVE-2023-24813](https://insights.sbomify.com/CVE-2023-24813/): URI validation failure on SVG parsing. Bypass of CVE-2023-23924 (critical 10.0)
- [CVE-2023-23924](https://insights.sbomify.com/CVE-2023-23924/): URI validation failure on SVG parsing in Dompdf (critical 10.0)
- [CVE-2021-3838](https://insights.sbomify.com/CVE-2021-3838/): PHAR Deserialization in dompdf/dompdf (critical 9.8)
- [CVE-2021-3902](https://insights.sbomify.com/CVE-2021-3902/): Improper Restriction of XML External Entity Reference in dompdf/dompdf (critical 9.8)
- [CVE-2022-28368](https://insights.sbomify.com/CVE-2022-28368/): Remote code injection in dompdf/dompdf (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-55554 and fix it if it is affected.

What it is: CVE-2026-55554 is a low-severity path traversal vulnerability in dompdf, published on 28 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55554 exists.

Affected packages and fixed versions:
- dompdf/dompdf (Packagist): affected all versions; fixed in 3.1.6
- dompdf/dompdf (Packagist): affected all versions; fixed in 3.1.6

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-55554/ (Markdown: https://insights.sbomify.com/CVE-2026-55554/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-55554
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-55554
- OSV: https://osv.dev/vulnerability/CVE-2026-55554

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-55554/
Summaries are generated and may contain mistakes; the official description above is the record.