VulnerabilityPublished 27 May 2025

CVE-2025-40911: RRWO Net::CIDR::Set · Improper Validation of Specified Type of Input

Affects RRWO Net::CIDR::SetSource CVE Database V5

Mentioned vulnerabilities

CVE-2021-47154

Not known to be exploited · CVSS 6.5 Medium.

Data as of 26 Oct 2026, 12:55 UTC

CVSS 3.1 base score

6.5Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 31% 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:L/I:L/A:N

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

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: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 27 May 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 26 Oct 2026.

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 or the CVSS exploit maturity 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
RRWO Net::CIDR::Set	Affected =0.10	Fixed in–

AI-suggested

European organizations should immediately audit their use of the Net::CIDR::Set Perl module, identifying all systems and applications that depend on it for IP address validation. Until an official patch is released, organizations should consider the following mitigations: 1) Implement additional validation layers for IP addresses, ensuring that leading zeros are either normalized or rejected to prevent octal interpretation. 2) Where feasible, replace Net::CIDR::Set with alternative, well-maintained libraries that correctly handle IP CIDR parsing. 3) Employ defense-in-depth by combining IP-based access control with other authentication and authorization mechanisms, such as multi-factor authentication and role-based access control. 4) Monitor network logs for suspicious access attempts that might indicate exploitation attempts involving malformed IP addresses. 5) Stay informed about vendor updates and apply patches promptly once available. 6) Conduct penetration testing focused on IP filtering bypass to validate the effectiveness of mitigations.

Description

Net::CIDR::Set versions 0.10 through 0.13 for Perl does not properly handle leading zero characters in IP CIDR address strings, which could allow attackers to bypass access control that is based on IP addresses. Leading zeros are used to indicate octal numbers, which can confuse users who are intentionally using octal notation, as well as users who believe they are using decimal notation. Net::CIDR::Set used code from Net::CIDR::Lite, which had a similar vulnerability CVE-2021-47154.

Impact

For European organizations, this vulnerability poses a risk to systems that rely on Perl-based Net::CIDR::Set for IP address filtering and access control, such as web applications, network appliances, or security tools that implement IP whitelisting or blacklisting. Unauthorized bypass of IP-based restrictions could lead to data breaches, unauthorized system access, or lateral movement within networks. This is particularly concerning for sectors with strict regulatory requirements on data confidentiality and access control, such as finance, healthcare, and critical infrastructure. The vulnerability could also undermine perimeter defenses in organizations that use IP filtering as a first line of defense. While the vulnerability does not directly impact availability, the potential for unauthorized access could lead to further exploitation or data exfiltration. The lack of known exploits in the wild suggests limited immediate risk, but the ease of exploitation and network accessibility mean that attackers could develop exploits rapidly once the vulnerability becomes widely known.

CWE-1287Improper Validation of Specified Type of Input (opens in a new tab)
Base weakness
The product receives input that is expected to be of a certain type, but it does not validate or incorrectly validates that the input is actually of the expected type.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 6 Jul 2025, 01:26 UTC

WeaknessesCWE-1287

Technical details

References

Community reviews

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