Parse Server: MFA recovery code single-use bypass via concurrent requests
Impact
An attacker who obtains a user's password and a single MFA recovery code can reuse that recovery code an unlimited number of times by sending concurrent login requests. This defeats the single-use design of recovery codes. The attack requires the user's password, a valid recovery code, and the ability to send concurrent requests within milliseconds.
Patches
The login handler now uses optimistic locking when updating auth data that contains consumed single-use tokens. If a concurrent request has already modified the recovery array, the update fails and the login is rejected.
Workarounds
There are no known workarounds.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | parse-server | >= 9.0.0, < 9.6.0-alpha.54, < 8.6.60 | 9.6.0-alpha.54, 8.6.60 |
References
- https://github.com/parse-community/parse-server/security/advisories/GHSA-2299-ghjr-6vjp
- https://nvd.nist.gov/vuln/detail/CVE-2026-33624
- https://github.com/parse-community/parse-server/pull/10275
- https://github.com/parse-community/parse-server/pull/10276
- https://github.com/parse-community/parse-server/commit/5e70094250a36bfcc14ecd49592be2b94fba66ff
- https://github.com/parse-community/parse-server/commit/fc3da35a81d5083b453e8967cabcc880f1a3bd0c
- https://github.com/parse-community/parse-server
- CVSS vector
CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N- Weakness (CWE)
CWE-367- Platform
- npm
- Package
parse-server- Disclosed
- 24.03.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-2299-ghjr-6vjp - CC BY 4.0
Vulnerability history: parse-server
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 116
- First → latest
- 06.2019 06.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 17
- High 49
- Medium 40
- Low 10
Disclosures per year
- 2019: 2
- 2020: 4
- 2021: 4
- 2022: 12
- 2023: 5
- 2024: 4
- 2025: 6
- 2026: 79
-
Parse Server: MFA recovery code single-use bypass via concurrent requests this entry
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