---
title: "CVE-2021-3902\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2021-3902?format=md
keywords: index, follow
---

# CVE-2021-3902

Publication date 15 November 2024

Last updated 25 August 2025

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**9.8 · Critical**

[Score breakdown](https://ubuntu.com/security/CVE-2021-3902?format=md#impact-score)

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## Description

An improper restriction of external entities (XXE) vulnerability in
dompdf/dompdf's SVG parser allows for Server-Side Request Forgery (SSRF)
and deserialization attacks. This issue affects all versions prior to
2.0.0. The vulnerability can be exploited even if the isRemoteEnabled
option is set to false. It allows attackers to perform SSRF, disclose
internal image files, and cause PHAR deserialization attacks.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| php-dompdf | 23.04 lunar | Not in release |
| 22.10 kinetic | Not affected |
| 22.04 LTS jammy | Not affected |
| 20.04 LTS focal | Not affected |
| 18.04 LTS bionic | Not affected |
| 16.04 LTS xenial | Not affected |
| 14.04 LTS trusty | Ignored end of standard support |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)
* [Patch details](https://ubuntu.com/security/CVE-2021-3902?format=md#patch-details)

### Patch details

For informational purposes only. We recommend not to cherry-pick updates. [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)

| Package | Patch details |
| --- | --- |
| php-dompdf | * Upstream:   [f56bc8e](https://github.com/dompdf/dompdf/commit/f56bc8e40be6c0ae0825e6c7396f4db80620b799) |

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

9.8 · Critical

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | Low |
  | Privileges required | None |
  | User interaction | None |
  | Scope | Unchanged |
  | Confidentiality impact | High |
  | Integrity impact | High |
  | Availability impact | High |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 9.8 · Critical |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3902)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2021-3902)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2021-3902)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2021-3902)

### Other references

* <https://github.com/dompdf/dompdf/issues/2564>
* <https://huntr.dev/bounties/a6071c07-806f-429a-8656-a4742e4191b1>
* <https://www.cve.org/CVERecord?id=CVE-2021-3902>