Parse Server has a login timing side-channel reveals user existence

Description

The 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.

Recommendation

Update the parse-server package to the latest compatible version. Followings are version details:

• Affected version(s): **< 8.6.74

  >= 9.0.0, < 9.8.0-alpha.6**

• Patched version(s): **8.6.74

  9.8.0-alpha.6**

References

• GHSA-mmpq-5hcv-hf2v
• CVE-2026-39321
• CWE-208
• CAPEC-310
• OWASP 2021-A6

Related Issues

• Parse Server email verification resend page leaks user existence - CVE-2026-33323
• Parse Server has an auth provider validation bypass on login via partial authData - CVE-2026-33409
• Parse Server has an MFA single-use token bypass via concurrent authData login requests - CVE-2026-34224
• Parse Server has role escalation and CLP bypass via direct `_Join` table write - CVE-2026-30966

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Tags:

npm

parse-server