GHSA-2299-ghjr-6vjp BIT-parse-2026-33624 CVE-2026-33624
Parse Server: MFA recovery code single-use bypass via concurrent requests
- Severity
- 0.0 / 10
- Low · CVSS 4.0
- Exploit chance (EPSS)
- 0.18%
- Chance of exploitation in the next 30 days. Higher than 7.80% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition
- Fix
9.6.0-alpha.54- Upgrade parse-server to this version or later
Description
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 versions
npm
| Package | Vulnerable | Fixed in |
|---|---|---|
| parse-server | >= 9.0.0, < 9.6.0-alpha.54 |
9.6.0-alpha.54 |
| parse-server | < 8.6.60 |
8.6.60 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
parse-server npm → 9.6.0-alpha.54
- npm
npm install parse-server@9.6.0-alpha.54- yarn
yarn add parse-server@9.6.0-alpha.54- pnpm
pnpm add parse-server@9.6.0-alpha.54
Severity breakdown
CVSS 4.0 0.0
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
- Attack vector
- Network
- Attack complexity
- High
- Attack requirements
- Present
- Privileges required
- High
- User interaction
- None
- Confidentiality (vulnerable system)
- None
- Integrity (vulnerable system)
- Low
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
CVSS 3.1 2.7
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:N
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- High
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
Weakness
CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition
The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.
How to prevent it
- Implementation: The most basic advice for TOCTOU vulnerabilities is to not perform a check before the use. This does not resolve the underlying issue of the execution of a function on a resource whose state and identity cannot be assured, but it does help to limit the false sense of security given by the check.
- Implementation: When the file being altered is owned by the current user and group, set the effective gid and uid to that of the current user and group when executing this statement.
- Architecture and Design: Limit the interleaving of operations on files from multiple processes.
- Implementation, Architecture and Design: If you cannot perform operations atomically and you must share access to the resource between multiple processes or threads, then try to limit the amount of time (CPU cycles) between the check and use of the resource. This will not fix the problem, but it could make it more difficult for an attack to succeed.
- Implementation: Recheck the resource after the use call to verify that the action was taken appropriately.
- Architecture and Design: Ensure that some environmental locking mechanism can be used to protect resources effectively.
- Implementation: Ensure that locking occurs before the check, as opposed to afterwards, such that the resource, as checked, is the same as it is when in use.
References
Advisories
Packages
Other links
- github.com/parse-community/parse-server/security/advisories/GHSA-2299-ghjr-6vjp
- github.com/parse-community/parse-server/pull/10275
- github.com/parse-community/parse-server/pull/10276
- github.com/parse-community/parse-server/commit/5e70094250a36bfcc14ecd49592be2b9…
- github.com/parse-community/parse-server/commit/fc3da35a81d5083b453e8967cabcc880…
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-r899-h629-j84r Parse Server vulnerable to stored XSS via malformed Content-Type bypassing file upload extension blocklist | Low | Also affects parse-server |
| GHSA-97pr-9hgg-3p8r parse-server: LiveQuery discloses object data to a subscriber across an ACL read-access change | Low | Also affects parse-server |
| GHSA-v8x7-r927-cc93 parse-server: Stored XSS via non-standard file extension bypassing file upload extension blocklist | Low | Also affects parse-server |
| GHSA-cgxm-vr2f-6fj8 parse-server: Denial of service via exponential-time processing of deeply nested query operators | High | Also affects parse-server |
| GHSA-wmwx-jr2p-4j4r parse-server: Relation `$relatedTo` query bypasses `protectedFields` and owning-object ACL | Medium | Also affects parse-server |
| GHSA-75v4-m273-5j49 parse-server: Endpoints `/login` and `/verifyPassword` disclose MFA secrets and protected fields when `_User` get is denied | Medium | Also affects parse-server |
| GHSA-7wqv-xjf3-x35v parse-server: Stored XSS via trailing-dot filename bypassing file upload extension blocklist | Low | Also affects parse-server |
| GHSA-p84r-h6rx-f2xr parse-server: Server option routeAllowList is bypassable through batch sub-requests | Medium | Also affects parse-server |
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