SB2025101337 - Incorrect Regular Expression in Sinatra
Published: October 13, 2025
Security Bulletin ID
SB2025101337
Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Denial of service
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) Incorrect Regular Expression (CVE-ID: CVE-2025-61921)
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to insufficient input validation when processing regular expressions in ETag generation within the If-Match and If-None-Match header parsing component. A remote attacker can pass specially crafted data to the application and perform regular expression denial of service (ReDos) attack.
Remediation
Install update from vendor's website.