CVE catalog

CVE-2025-61921

ruby-sinatra: CVE-2025-61921

Severity: Medium · CVSS 5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Published: Oct 10, 2025, 7:28:10 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.50% · Oct 25, 2026

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.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	ruby-sinatra	sid	`4.2.1-5`	fixed
Debian	ruby-sinatra	forky	`4.2.1-5`	fixed
Debian	ruby-sinatra	trixie	`4.1.1-5`	vulnerable
Debian	ruby-sinatra	bookworm	`3.0.5-3+deb12u1`	fixed
Cpe	sinatra	Not reported	`4.2.0`	fixed
Ubuntu	ruby-sinatra	pro	`2.0.8.1-2`	vulnerable
Ubuntu	ruby-sinatra	pro	`2.0.8.1-2+deb11u1build0.22.04.1`	vulnerable
Ubuntu	ruby-sinatra	pro	`2.0.8.1-2+deb11u1ubuntu0.1~esm1`	fixed
Ubuntu	ruby-sinatra	26.04	`4.1.1-5`	vulnerable
Ubuntu	ruby-sinatra	26.04	`4.2.1-1`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	ruby-sinatra	source	sid	`4.2.1-1`	not yet assigned	Not reported	[1118290]
Debian	ruby-sinatra	source	forky	`4.2.1-1`	not yet assigned	Not reported	[1118290]
Debian	ruby-sinatra	source	trixie	`(unfixed)`	not yet assigned	Not reported	[1118290]
Debian	ruby-sinatra	source	bookworm	`3.0.5-3+deb12u1`	not yet assigned	Not reported	[1118290]
Cpe	sinatra	cpe	Not reported	`4.2.0`	Not reported	NVD-CVE-2025-61921	Not reported
Ubuntu	ruby-sinatra	deb	pro	`2.0.8.1-2+deb11u1ubuntu0.1~esm1`	Not reported	UBUNTU-CVE-2025-61921	Not reported
Ubuntu	ruby-sinatra	deb	26.04	`4.2.1-1`	Not reported	UBUNTU-CVE-2025-61921	Not reported

[Debian bug #1118290]

Notes

[trixie] ruby-sinatra: Minor issue; only a problem together with Ruby < 3.2

OpenFactory catalog packages

[Debian 13 (Trixie)]

[ruby-rack-protection]Affected
Source package: [ruby-sinatra]
Details (2)
- 4.1.1-5 · all · trixie
  Affected
  dsa · ruby-sinatra · debian · 13
- 4.1.1-5 · all · trixie
  Affected
  dsa · ruby-sinatra · debian · 13
[ruby-sinatra]Affected
Details (2)
- 4.1.1-5 · all · trixie
  Affected
  dsa · ruby-sinatra · debian · 13
- 4.1.1-5 · all · trixie
  Affected
  dsa · ruby-sinatra · debian · 13
[ruby-sinatra-contrib]Affected
Source package: [ruby-sinatra]
Details (2)
- 4.1.1-5 · all · trixie
  Affected
  dsa · ruby-sinatra · debian · 13
- 4.1.1-5 · all · trixie
  Affected
  dsa · ruby-sinatra · debian · 13

[Debian 12 (Bookworm)]

[ruby-rack-protection]Fixed
Source package: [ruby-sinatra]
Details (2)
- 3.0.5-3+deb12u1 · all · bookworm
  Fixed · Fixed: 3.0.5-3+deb12u1
  dsa · ruby-sinatra · debian · bookworm; dsa · ruby-sinatra · debian · 12
- 3.0.5-3+deb12u1 · all · bookworm
  Fixed · Fixed: 3.0.5-3+deb12u1
  dsa · ruby-sinatra · debian · bookworm; dsa · ruby-sinatra · debian · 12
[ruby-sinatra]Fixed
Details (2)
- 3.0.5-3+deb12u1 · all · bookworm
  Fixed · Fixed: 3.0.5-3+deb12u1
  dsa · ruby-sinatra · debian · bookworm; dsa · ruby-sinatra · debian · 12
- 3.0.5-3+deb12u1 · all · bookworm
  Fixed · Fixed: 3.0.5-3+deb12u1
  dsa · ruby-sinatra · debian · bookworm; dsa · ruby-sinatra · debian · 12
[ruby-sinatra-contrib]Fixed
Source package: [ruby-sinatra]
Details (2)
- 3.0.5-3+deb12u1 · all · bookworm
  Fixed · Fixed: 3.0.5-3+deb12u1
  dsa · ruby-sinatra · debian · bookworm; dsa · ruby-sinatra · debian · 12
- 3.0.5-3+deb12u1 · all · bookworm
  Fixed · Fixed: 3.0.5-3+deb12u1
  dsa · ruby-sinatra · debian · bookworm; dsa · ruby-sinatra · debian · 12

Observed: Oct 24, 2026, 5:22:25 PM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX]