Vulnerability · Published Apr 7, 2026 · Assigned by GitHub_M
CVE-2026-39321Parse Server has a login timing side-channel reveals user existence
Medium 6.3
In plain English
A medium-severity security flaw in parse-server from parse-community. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 15% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to 9.8.0-alpha.6 and 8.6.74, he login endpoint response time differs measurably depending on whether the submitted username or email exists in the database. When a user is not found, the server responds immediately. When a user exists but the password is wrong, a bcrypt comparison runs first, adding significant latency. This timing difference allows an unauthenticated attacker to enumerate valid usernames. This vulnerability is fixed in 9.8.0-alpha.6 and 8.6.74.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | parse-server | 9.8.0-alpha.6 | GHSA-mmpq-5hcv-hf2v |
| npm | parse-server | 8.6.74 | GHSA-mmpq-5hcv-hf2v |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| parse-community | parse-server | >= 9.0.0, < 9.8.0-alpha.6< 8.6.74 |
Weakness: CWE-208 · Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
References
- https://github.com/parse-community/parse-server/security/advisories/GHSA-mmpq-5hcv-hf2v x_refsource_CONFIRM
- https://github.com/parse-community/parse-server/pull/10398 x_refsource_MISC
- https://github.com/parse-community/parse-server/pull/10399 x_refsource_MISC