# CVE-2021-29434: Improper validation of URLs ('Cross-site Scripting') in Wagtail rich text fields

> A malicious admin user can inject JavaScript into rich text fields due to missing server-side URL validation, leading to code execution.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 19 Apr 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-wq5h-f9p5-q7fx, PYSEC-2021-114

## What is CVE-2021-29434?

CVE-2021-29434 is a medium-severity cross-site scripting vulnerability in wagtail, published on 19 Apr 2021. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

### Official description

Wagtail is a Django content management system. In affected versions of Wagtail, when saving the contents of a rich text field in the admin interface, Wagtail does not apply server-side checks to ensure that link URLs use a valid protocol. A malicious user with access to the admin interface could thus craft a POST request to publish content with `javascript:` URLs containing arbitrary code. The vulnerability is not exploitable by an ordinary site visitor without access to the Wagtail admin. See referenced GitHub advisory for additional details, including a workaround. Patched versions have been released as Wagtail 2.11.7 (for the LTS 2.11 branch) and Wagtail 2.12.4 (for the current 2.12 branch).

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2021-29434?

5 open source packages ship an affected version, including wagtail. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `wagtail` | PyPI | All versions | 2.11.7 |
| `wagtail` | PyPI | All versions | 2.11.7 |
| `wagtail` | PyPI | From 2.11 | 2.11.7, 2.11.6, 2.12.4 |
| `wagtail` | PyPI | From 2.12 | 2.12.4 |
| `wagtail` | PyPI | From 2.12 | 2.12.4 |

Products: Torchbox Wagtail.

## How do I fix CVE-2021-29434?

Upgrade wagtail to a fixed version for your release line: 2.11.7, 2.11.6 or 2.12.4.

## Is CVE-2021-29434 being exploited?

There is no known exploitation of CVE-2021-29434 in the wild and no public exploit code.

## Other vulnerabilities in wagtail

- [CVE-2026-54263](https://insights.sbomify.com/CVE-2026-54263/): Wagtail: Reflected XSS in dynamic image URL generator view (high 7.3)
- [CVE-2026-54261](https://insights.sbomify.com/CVE-2026-54261/): Wagtail: Improper permission handling in image preview (medium 6.5)
- [CVE-2026-44197](https://insights.sbomify.com/CVE-2026-44197/): Wagtail: Improper permission handling when comparing revisions (medium 6.5)
- [CVE-2026-44199](https://insights.sbomify.com/CVE-2026-44199/): Wagtail: Improper permission handling when deleting form submissions (medium 6.5)
- [CVE-2026-44200](https://insights.sbomify.com/CVE-2026-44200/): Wagtail: Improper permission handling when copying pages (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-29434 and fix it if it is affected.

What it is: CVE-2021-29434 is a medium-severity cross-site scripting vulnerability in wagtail, published on 19 Apr 2021. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-29434 in the wild and no public exploit code.

Affected packages and fixed versions:
- wagtail (PyPI): affected all versions; fixed in 2.11.7
- wagtail (PyPI): affected all versions; fixed in 2.11.7
- wagtail (PyPI): affected from 2.11; fixed in 2.11.7, 2.11.6, 2.12.4
- wagtail (PyPI): affected from 2.12; fixed in 2.12.4
- wagtail (PyPI): affected from 2.12; fixed in 2.12.4

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-2021-29434/ (Markdown: https://insights.sbomify.com/CVE-2021-29434/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-29434
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-29434
- OSV: https://osv.dev/vulnerability/CVE-2021-29434

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-29434/
Summaries are generated and may contain mistakes; the official description above is the record.