CVE-2025-24294 — resolv
MEDIUMCVE-2025-24294 is a medium-severity (CVSS 5.3) Uncontrolled Resource Consumption vulnerability in resolv. A fix is available for resolv — see the affected versions and patch details below.
resolv vulnerable to DoS via insufficient DNS domain name length validation
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-24294.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2025-24294 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,238 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
resolv💎resolv💎resolvReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
The attack vector is a potential Denial of Service (DoS). 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 Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | resolv | all versions | 0.2.3bundle update resolv --conservative |
| 💎RubyGems | resolv | ≥ 0.4.0&&< 0.6.2 | 0.6.2bundle update resolv --conservative |
| 💎RubyGems | resolv | ≥ 0.3.0&&< 0.3.1 | 0.3.1bundle update resolv --conservative |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for resolv, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update resolv to 0.2.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-24294 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-24294 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-24294. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 10 | ruby-0:3.3.10-11.el10_1 | RHSA-2025:23141 |
| Red Hat Enterprise Linux 10.0 Extended Update Support | ruby-0:3.3.10-11.el10_0 | RHSA-2025:23927 |
| Red Hat Enterprise Linux 8 | ruby:3.3-8100020251124151715.489197e6 | RHSA-2025:23062 |
| Red Hat Enterprise Linux 9 | ruby:3.3-9070020251113101221.9 | RHSA-2025:23063 |
| Red Hat Enterprise Linux 9.6 Extended Update Support | ruby:3.3-9060020251210162455.9 | RHSA-2025:23648 |
Frequently Asked Questions
Is CVE-2025-24294 in your dependencies?
O3 Security finds CVE-2025-24294 across RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.