CVE-2025-61921 Vulnerability Analysis & Exploit Details

CVE-2025-61921
Vulnerability Scoring

Analysis In Progress
Analysis In Progress

Attack Complexity Details

  • Attack Complexity:
    Attack Complexity Analysis In Progress
  • Attack Vector:
    Attack Vector Under Analysis
  • Privileges Required: None
    No authentication is required for exploitation.
  • Scope:
    Impact is confined to the initially vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2025-61921 Details

Status: Received on 10 Oct 2025, 20:15 UTC

Published on: 10 Oct 2025, 20:15 UTC

CVSS Release:

CVE-2025-61921 Vulnerability Summary

CVE-2025-61921: 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.

Assessing the Risk of CVE-2025-61921

Access Complexity Graph

The exploitability of CVE-2025-61921 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2025-61921

No exploitability data is available for CVE-2025-61921.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2025-61921, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2025-61921, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: None
    CVE-2025-61921 does not compromise confidentiality.
  • Integrity: None
    CVE-2025-61921 does not impact data integrity.
  • Availability: None
    CVE-2025-61921 does not affect system availability.

CVE-2025-61921 References

External References

CWE Common Weakness Enumeration

CWE-1333

CAPEC Common Attack Pattern Enumeration and Classification

  • Regular Expression Exponential Blowup CAPEC-492 An adversary may execute an attack on a program that uses a poor Regular Expression(Regex) implementation by choosing input that results in an extreme situation for the Regex. A typical extreme situation operates at exponential time compared to the input size. This is due to most implementations using a Nondeterministic Finite Automaton(NFA) state machine to be built by the Regex algorithm since NFA allows backtracking and thus more complex regular expressions.

Protect Your Infrastructure against CVE-2025-61921: Combat Critical CVE Threats

Stay updated with real-time CVE vulnerabilities and take action to secure your systems. Enhance your cybersecurity posture with the latest threat intelligence and mitigation techniques. Develop the skills necessary to defend against CVEs and secure critical infrastructures. Join the top cybersecurity professionals safeguarding today's infrastructures.

Other 5 Recently Published CVEs Vulnerabilities

  • CVE-2025-9554 – Vulnerability in Drupal Owl Carousel 2.This issue affects Owl Carousel 2: *.*.
  • CVE-2025-9553 – Vulnerability in Drupal API Key manager.This issue affects API Key manager: *.*.
  • CVE-2025-9552 – Vulnerability in Drupal Synchronize composer.Json With Contrib Modules.This issue affects Synchronize composer.Json With Contrib Modules: *.*.
  • CVE-2025-9551 – Improper Restriction of Excessive Authentication Attempts vulnerability in Drupal Protected Pages allows Brute Force.This issue affects Protected P...
  • CVE-2025-9550 – Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Drupal Facets allows Cross-Site Scripting (XS...