---
id: "CVE-2026-123487"
page: "https://infrastack.ai/live/CVE-2026-123487"
kind: "vulnerability"
aliases: ["CVE-2026-123487"]
title: "Parse Server: email regex lets long input block Node.js event loop"
severity: "high"
cvss: 8.7
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["backend-as-a-service", "node.js", "package", "parse-server", "self-hosted"]
not_affected_if: ["no-public-signup", "patched-version"]
published_at: "2026-11-06T15:17:17+00:00"
first_seen_at: "2026-11-06T15:42:43+00:00"
updated_at: "2026-11-06T15:44:06+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-123487", "first_seen_at": "2026-11-06T15:42:43+00:00"}]
exploit_sources: []
---

# Parse Server: email regex lets long input block Node.js event loop

Link for people: https://infrastack.ai/live/CVE-2026-123487 (this .md is for agents)

Parse Server validates user email addresses with a regular expression whose run time grows quadratically with input length and has no length limit. A long crafted email on sign-up or email update blocks the Node.js event loop, denying service to all clients.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed Parse Server version with `npm ls parse-server`
- Look for `parse-server` in `package.json` and the lockfile to confirm the version range in use

## Fix

- Parse Server `8.6.115` or later on the 8.x line
- Parse Server `9.10.7-alpha.1` or later on the 9.x line

## Timeline

- 2026-11-06T15:42:43+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-123487

## Documents

- [advisory] Vendor advisory: github.com https://github.com/parse-community/parse-server/security/advisories/GHSA-9492-427f-466x
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/parse-server-9.0.0-before-9.10.7-alpha.1-redos-via-email-validation-regex

## From the sources

Parse Server before 8.6.115 and 9.0.0 before 9.10.7-alpha.1 validates user email address format with a regular expression whose run time grows quadratically with input length and that is applied without a length limit. An unauthenticated attacker who knows the application ID can send a sign-up request, or a logged-in user can update their own email, with a long crafted email address to block the Node.js event loop and deny service to all clients.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_