# CVE-2026-53724: Parse Server: Stored XSS via trailing-dot filename bypassing file upload extension blocklist

> Attackers can bypass file upload restrictions to store malicious files that trigger stored XSS when served with active content types.

- **Severity:** Low 2.1 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:L/VA:N/SC:L/SI:L/SA: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:** 12 Jun 2026
- **Updated:** 12 Jun 2026
- **Also known as:** BIT-parse-2026-53724, GHSA-7wqv-xjf3-x35v

## What is CVE-2026-53724?

CVE-2026-53724 is a low-severity cross-site scripting vulnerability in parse-community parse-server, published on 12 Jun 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

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.79 and 9.9.1-alpha.4, the default file upload extension blocklist can be bypassed by appending a trailing dot to a filename whose extension would otherwise be blocked (e.g. poc.svg.). The trailing dot causes the extension parser to extract an empty string, which short-circuits the blocklist check, and the attacker-controlled Content-Type is forwarded to the storage adapter unchanged. Storage adapters that persist and serve the provided Content-Type (such as S3 or GCS) then serve the file with an active type such as image/svg+xml, enabling stored XSS when a victim opens the file URL. The default GridFS adapter is not affected because it sets X-Content-Type-Options: nosniff on responses. This issue has been patched in versions 8.6.79 and 9.9.1-alpha.4.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation), CWE-434 (Unrestricted Upload of File with Dangerous Type)

## Which versions are affected by CVE-2026-53724?

5 open source packages ship an affected version, including parse-server and parse.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `parse-server` | npm | All versions | 8.6.79 |
| `parse-server` | npm | All versions | 8.6.79 |
| `parse-server` | npm | From 9.0.0 | 9.9.1-alpha.4 |
| `parse-server` | npm | From 9.0.0 | 9.9.1-alpha.4 |
| `parse` | Bitnami | All versions | 8.6.79, 9.9.1 |

## How do I fix CVE-2026-53724?

Upgrade parse-server to a fixed version for your release line: 8.6.79 or 9.9.1-alpha.4.

## Is CVE-2026-53724 being exploited?

There is no known exploitation of CVE-2026-53724 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53724 and fix it if it is affected.

What it is: CVE-2026-53724 is a low-severity cross-site scripting vulnerability in parse-community parse-server, published on 12 Jun 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-2026-53724 in the wild and no public exploit code.

Affected packages and fixed versions:
- parse-server (npm): affected all versions; fixed in 8.6.79
- parse-server (npm): affected all versions; fixed in 8.6.79
- parse-server (npm): affected from 9.0.0; fixed in 9.9.1-alpha.4
- parse-server (npm): affected from 9.0.0; fixed in 9.9.1-alpha.4
- parse (Bitnami): affected all versions; fixed in 8.6.79, 9.9.1

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-2026-53724/ (Markdown: https://insights.sbomify.com/CVE-2026-53724/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53724
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53724
- OSV: https://osv.dev/vulnerability/CVE-2026-53724

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53724/
Summaries are generated and may contain mistakes; the official description above is the record.