# CVE-2026-75526: django CMS: Stored XSS in edit-mode plugin exception rendering

> Stored XSS in django CMS edit mode allows attackers to execute arbitrary scripts in an editor's browser via unescaped exception messages.

- **Severity:** Medium 4.4 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 20 Aug 2026
- **Updated:** 20 Aug 2026
- **Also known as:** GHSA-hvq6-2r72-p2x7, PYSEC-2026-3825

## What is CVE-2026-75526?

CVE-2026-75526 is a medium-severity cross-site scripting vulnerability in django-cms, published on 20 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

django CMS is an easy-to-use and developer-friendly enterprise content management system powered by Django. From 5.0.8 until 5.0.9, ContentRenderer.render_placeholder in cms/plugin_rendering.py can pass stored, attacker-controlled values to ContentRenderer.render_exception when plugin rendering fails in edit mode. Values from get_short_description(), the exception message, the placeholder, or placeholder.source are interpolated into a cms-rendering-exception heading and later returned through mark_safe. Because the heading is not escaped, stored HTML executes in an editor’s browser, and settings.DEBUG does not prevent the custom heading from rendering. The fix uses format_html to escape the message before safe placeholder output is returned. This issue is fixed in versions 5.0.9.

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

## Which versions are affected by CVE-2026-75526?

3 open source packages ship an affected version, including django-cms.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `django-cms` | PyPI | From 5.0.8 | 5.0.9 |
| `django-cms` | PyPI | From 5.0.8 | 5.0.9 |
| `django-cms` | PyPI | From 5.0.8 | 5.0.9 |

## How do I fix CVE-2026-75526?

Upgrade django-cms to 5.0.9 or later.

## Is CVE-2026-75526 being exploited?

There is no known exploitation of CVE-2026-75526 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-75526 and fix it if it is affected.

What it is: CVE-2026-75526 is a medium-severity cross-site scripting vulnerability in django-cms, published on 20 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-75526 in the wild and no public exploit code.

Affected packages and fixed versions:
- django-cms (PyPI): affected from 5.0.8; fixed in 5.0.9
- django-cms (PyPI): affected from 5.0.8; fixed in 5.0.9
- django-cms (PyPI): affected from 5.0.8; fixed in 5.0.9

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-2026-75526/ (Markdown: https://insights.sbomify.com/CVE-2026-75526/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-75526
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-75526
- OSV: https://osv.dev/vulnerability/CVE-2026-75526

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-75526/
Summaries are generated and may contain mistakes; the official description above is the record.