Vulnerability · Published Apr 15, 2026 · Assigned by GitHub_M
CVE-2026-33877ApostropheCMS: User Enumeration via Timing Side Channel in Password Reset Endpoint
Low 3.7
In plain English
A low-severity security flaw in apostrophe from apostrophecms. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 30% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | apostrophe | 4.29.0 | GHSA-mj7r-x3h3-7rmr |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| apostrophecms | apostrophe | < 4.29.0 |
Weakness: CWE-208 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N