GHSA-w73w-g5xw-rwhf BIT-parse-2026-34224 CVE-2026-34224

Parse Server has an MFA single-use token bypass via concurrent authData login requests

Medium npm

Severity: 0.0 / 10; Medium · CVSS 4.0
Exploit chance (EPSS): 0.32%; Chance of exploitation in the next 30 days. Higher than 24.64% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition
Fix: 9.7.0-alpha.8; Upgrade parse-server to this version or later

Description

Impact

An attacker who possesses a valid authentication provider token and a single MFA recovery code or SMS one-time password can create multiple authenticated sessions by sending concurrent login requests via the authData login endpoint. This defeats the single-use guarantee of MFA recovery codes and SMS one-time passwords, allowing session persistence even after the legitimate user revokes detected sessions.

Patches

The fix adds optimistic locking to the authData login path, ensuring that concurrent database updates for the same user fail when the original MFA token array has already been modified by another request.

Workarounds

There is no known workaround.

Affected versions

npm

Package	Vulnerable	Fixed in
parse-server	`>= 9.0.0, < 9.7.0-alpha.8`	`9.7.0-alpha.8`
parse-server	`< 8.6.64`	`8.6.64`

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 → `9.7.0-alpha.8`

npm

npm install parse-server@9.7.0-alpha.8

yarn

yarn add parse-server@9.7.0-alpha.8

pnpm

pnpm add parse-server@9.7.0-alpha.8

Severity breakdown

CVSS 4.0 0.0

CVSS:4.0/AV:N/AC:H/AT:N/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

Attack vector: Network
Attack complexity: High
Attack requirements: None
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 4.4

CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:N

Attack vector: Network
Attack complexity: High
Privileges required: High
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: High
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

nvd.nist.gov/vuln/detail/CVE-2026-34224

Packages

github.com/parse-community/parse-server

Timeline

Mar 29, 2026 Published
Jul 24, 2026 Last updated by the source
Nov 1, 2026 Latest EPSS score

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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