parse-server: Stored XSS via trailing-dot filename bypassing file upload extension blocklist
Impact
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.
Patches
A filename ending in a dot is now treated as extensionless. When the parser produces an empty extension, the request handler falls back to validating the Content-Type subtype against the configured extension blocklist, matching the path that already catches truly extensionless uploads with a dangerous Content-Type. This is a follow-up to the previous fix GHSA-vr5f-2r24-w5hc.
Workarounds
Configure the storage adapter or CDN to derive Content-Type from the filename extension instead of using the stored Content-Type, or replace the default blocklist with an explicit allowlist of needed file extensions.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | parse-server | >= 9.0.0, < 9.9.1-alpha.4, < 8.6.79 | 9.9.1-alpha.4, 8.6.79 |
References
- https://github.com/parse-community/parse-server/security/advisories/GHSA-7wqv-xjf3-x35v
- https://nvd.nist.gov/vuln/detail/CVE-2026-53724
- https://github.com/parse-community/parse-server/pull/10489
- https://github.com/parse-community/parse-server/pull/10490
- https://github.com/parse-community/parse-server
- CVSS vector
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- Weakness (CWE)
CWE-434, CWE-79- Platform
- npm
- Package
parse-server- Disclosed
- 19.06.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-7wqv-xjf3-x35v - CC BY 4.0
Vulnerability history: parse-server
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 116
- First → latest
- 06.2019 06.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 17
- High 49
- Medium 40
- Low 10
Disclosures per year
- 2019: 2
- 2020: 4
- 2021: 4
- 2022: 12
- 2023: 5
- 2024: 4
- 2025: 6
- 2026: 79
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