Sinatra is a domain-specific language for creating web applications in Ruby. In versions prior to 4.2.0, there is a denial of service vulnerability in the `If-Match` and `If-None-Match` header parsing component of Sinatra, if the `etag` method is used when constructing the response. Carefully crafted input can cause `If-Match` and `If-None-Match` header parsing in Sinatra to take an unexpected amount of time, possibly resulting in a denial of service attack vector. This header is typically involved in generating the `ETag` header value. Any applications that use the `etag` method when generating a response are impacted. Version 4.2.0 fixes the issue.
Advisories
Source ID Title
Github GHSA Github GHSA GHSA-mr3q-g2mv-mr4q Sinatra is vulnerable to ReDoS through ETag header value generation
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Fri, 10 Oct 2025 21:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 10 Oct 2025 19:45:00 +0000

Type Values Removed Values Added
Description Sinatra is a domain-specific language for creating web applications in Ruby. In versions prior to 4.2.0, there is a denial of service vulnerability in the `If-Match` and `If-None-Match` header parsing component of Sinatra, if the `etag` method is used when constructing the response. Carefully crafted input can cause `If-Match` and `If-None-Match` header parsing in Sinatra to take an unexpected amount of time, possibly resulting in a denial of service attack vector. This header is typically involved in generating the `ETag` header value. Any applications that use the `etag` method when generating a response are impacted. Version 4.2.0 fixes the issue.
Title Sinatra has ReDoS vulnerability in ETag header value generation
Weaknesses CWE-1333
References
Metrics cvssV4_0

{'score': 2.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2025-10-10T20:54:47.627Z

Reserved: 2025-10-03T22:21:59.615Z

Link: CVE-2025-61921

cve-icon Vulnrichment

Updated: 2025-10-10T20:54:28.101Z

cve-icon NVD

Status : Received

Published: 2025-10-10T20:15:38.067

Modified: 2025-10-10T20:15:38.067

Link: CVE-2025-61921

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.