CVE-2025-24294

A denial of service vulnerability has been discovered in the resolv gem bundled with Ruby.

Details

The vulnerability is caused by an insufficient check on the length of a decompressed domain name within a DNS packet.

An attacker can craft a malicious DNS packet containing a highly compressed domain name. When the resolv library parses such a packet, the name decompression process consumes a large amount of CPU resources, as the library does not limit the resulting
length of the name.

This resource consumption can cause the application thread to become unresponsive, resulting in a Denial of Service condition.

Affected Version

The vulnerability affects the resolv gem bundled with the following Ruby series:

• Ruby 3.2 series: resolv version 0.2.2 and earlier
• Ruby 3.3 series: resolv version 0.3.0
• Ruby 3.4 series: resolv version 0.6.1 and earlier

Credits

Thanks to Manu for discovering this issue.

History

Originally published at 2025-07-08 07:00:00 (UTC)

Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.

CVE-2025-24294 has a CVSS score of 5.3 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.2.3, 0.6.2, 0.3.1); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2025-24294? CVE-2025-24294 is a medium-severity uncontrolled resource consumption vulnerability in resolv (rubygems), affecting versions < 0.2.3. It is fixed in 0.2.3, 0.6.2, 0.3.1. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
2. How severe is CVE-2025-24294? CVE-2025-24294 has a CVSS score of 5.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of resolv are affected by CVE-2025-24294? resolv (rubygems) versions < 0.2.3 is affected.
4. Is there a fix for CVE-2025-24294? Yes. CVE-2025-24294 is fixed in 0.2.3, 0.6.2, 0.3.1. Upgrade to this version or later.
5. Is CVE-2025-24294 exploitable, and should I be worried? Whether CVE-2025-24294 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2025-24294 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2025-24294?
   • Upgrade resolv to 0.2.3 or later
   • Upgrade resolv to 0.6.2 or later
   • Upgrade resolv to 0.3.1 or later