CVE-2025-24294VulnerabilityPublished 12 Jul 2025Updated 16 Jul 2025

CVE-2025-24294: Ruby resolv · Vulnerability

Affects Ruby resolvSource CVE Database V5

Not known to be exploited · CVSS 7.5 High.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.6% chance of exploitation in 30 days – higher than 51% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 12 Jul 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
RubyGemsresolv`pkg:gem/resolv`Other threats	Affected =0.2 =0.3.0 =0.6	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate CVE-2025-24294, European organizations should take immediate and specific actions beyond generic advice: 1) Audit all Ruby applications and services to identify usage of the 'resolv' library versions 0.2, 0.3.0, or 0.6. 2) Where possible, upgrade to a patched or newer version of the 'resolv' library once available from the Ruby maintainers. 3) Implement network-level protections such as DNS packet inspection and rate limiting to detect and block suspicious DNS packets with abnormal compression or size characteristics. 4) Employ application-level timeouts and resource usage limits to prevent a single thread or process from becoming unresponsive due to excessive CPU consumption. 5) Monitor application logs and performance metrics for signs of resource exhaustion or unusual DNS processing delays. 6) Engage with Ruby community and security advisories to stay informed about patches or mitigations. 7) Consider isolating or sandboxing DNS resolution components to minimize impact on critical application components. These steps will help reduce the risk and impact of exploitation until official patches are released.

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.

Impact

For European organizations, the impact of CVE-2025-24294 can be significant, especially for those relying on Ruby-based applications for critical services such as web hosting, internal tools, or network infrastructure. The vulnerability enables remote attackers to cause Denial of Service conditions without authentication or user interaction, potentially disrupting business operations, degrading service availability, and impacting customer trust. Organizations in sectors with high reliance on Ruby, such as fintech, e-commerce, and software development companies, may experience service outages or degraded performance. Additionally, the DoS could be leveraged as part of a larger attack chain to distract or exhaust resources during more complex intrusions. The lack of patches at the time of disclosure increases the risk window. Given the network-based attack vector, attackers can exploit this vulnerability remotely, increasing the threat surface. The vulnerability does not impact confidentiality or integrity directly but poses a high risk to availability, which can have cascading effects on business continuity and compliance with service-level agreements (SLAs).

CWE-400Uncontrolled Resource Consumption (opens in a new tab)
Class weaknessLikelihood of exploit: High
The product does not properly control the allocation and maintenance of a limited resource.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design
Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place.
Architecture and Design
Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or; uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed.
Architecture and Design
Ensure that protocols have specific limits of scale placed on them.
OWASP Cheat Sheets
File Upload (opens in a new tab)
OWASP ASVS 4.0.3
V12.1.1 (opens in a new tab)
Attack patterns
XML Ping of the Death (opens in a new tab)
Regular Expression Exponential Blowup (opens in a new tab)
Sustained Client Engagement (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

ruby-lang.org/en/news/2025/07/08/dos-resolv-cve-2025-24294/ (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 19 Jul 2025, 20:49 UTC

WeaknessesCWE-400

Technical details

References

Community reviews

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