Connect your agent
AdvisoriesCriticalCheck your lockfilePluginHow it worksPricing Connect your agent

Advisory record · GHSA-r899-h629-j84r

Parse Server vulnerable to stored XSS via malformed Content-Type bypassing file upload extension blocklist

CVSS 2.1 LowEPSS 0.0042 · 35th percentile

Published by the GitHub Advisory Database at 29 Oct 2026, 16:33 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
parse-servernpm>=9.0.0, <9.10.0-alpha.2 || <8.6.849.10.0-alpha.2, 8.6.84
Identifiers
GHSA-r899-h629-j84r · BIT-parse-2026-61448 · CVE-2026-61448
Weakness (CWE)
CWE-434
Tags
Published
29 Oct 2026
Updated
29 Oct 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Parse Server, the npm package parse-server, versions below 8.6.84 and from 9.0.0 up to but not including 9.10.0-alpha.2, has a stored cross-site scripting flaw in its file upload handling. A malformed Content-Type on an uploaded file bypassed the extension blocklist, and on storage adapters that persist that header, such as Amazon S3, Google Cloud Storage, or Azure Blob Storage, a user permitted to upload files can store HTML-with-script that runs against other users who open the file URL. Upgrade to parse-server 8.6.84 or 9.10.0-alpha.2 or later, which reject malformed Content-Type values.

Written 31 Oct 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

ScoreRatingCVSSVectorSource
2.1 Low 4.0 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 CNA (VulnCheck)
  • CISA KEV Not listed.
  • EPSS 0.0042, the 35th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 13:32 UTC First seen by agentprime
  2. 31 Oct 2026, 13:32 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.