SB2026040745 - Time-of-check Time-of-use (TOCTOU) Race Condition in Parse Server

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Main Vulnerability Database SB2026040745

SB2026040745 - Time-of-check Time-of-use (TOCTOU) Race Condition in Parse Server

Published: April 7, 2026

Security Bulletin ID SB2026040745
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Time-of-check Time-of-use (TOCTOU) Race Condition (CVE-ID: CVE-2026-33624)

CWE-ID: CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear


The vulnerability allows a remote user to bypass single-use restrictions on MFA recovery codes.

The vulnerability exists due to a time-of-check time-of-use race condition in the login handler when processing concurrent login requests that use an MFA recovery code. A remote privileged user can send concurrent login requests with a valid password and recovery code to bypass single-use restrictions on MFA recovery codes.

Exploitation requires possession of the user's password, a valid recovery code, and the ability to issue concurrent requests within milliseconds.


Remediation

Install update from vendor's website.

References