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GHSA-mr3q-g2mv-mr4q

LowCVSS 2.7 / 10
Published Oct 10, 2025·Last modified Feb 4, 2026
Affected Components(0)

No affected components available

Description

Summary

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 and you are using Ruby < 3.2.

Details

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 if they are using Ruby below version 3.2.

Resources

  • https://github.com/sinatra/sinatra/issues/2120 (report)
  • https://github.com/sinatra/sinatra/pull/2121 (fix)
  • https://github.com/sinatra/sinatra/pull/1823 (older ReDoS vulnerability)
  • https://bugs.ruby-lang.org/issues/19104 (fix in Ruby >= 3.2)
Risk Scores
Base Score
2.7

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability.

Threat Intelligence
2.7

Limited exploitation activity has been observed. Close monitoring and planned remediation are recommended.

EPSS
0.46%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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