CVE-2025-61921 - CVE House
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Status published Low CVE-2025-61921

Sinatra has ReDoS vulnerability in ETag header value generation

Vulnerability 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.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

No credits recorded in the NVD database.

Affected Vendor

Affected Software

sinatra
Vulnerable Versions:
< 4.2.0

Timeline

Official Publish: October 10th, 2025
Last Modified: October 10th, 2025
Added to House: July 22nd, 2026

CVSS Vectors

Weaknesses (CWE)