CVE Tools

CVE-2025-61921

Sinatra has ReDoS vulnerability in ETag header value generation

Published: Oct 10, 2025Updated: Oct 31, 2025 Sources: CVE List NVD GHSA BDUCWE-1333

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.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High

Weaknesses

Affected Products

sinatrarboss-projectOSS Librariesaka sinatra, rack-protection
rubygemspackage-ecosystemOSS Libraries
sinatraoss-projectOSS Librariesaka sinatrajs
сообщество свободного программного обеспеченияoss-projectOperating Systemsaka сообщество свободного программного обеспечения, fsf

Attack Graph

Products CVE Techniques Tactics

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Exploitability

2 exploit sources identified

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View exploit details
Official Patch Available

MITRE ATT&CK

1 technique
Impact
View detailed technique mapping

References

and 17 more references View all →

Timeline

Published
Oct 10, 2025
Last Updated
Oct 31, 2025

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