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Net CVE-2021-4456

MEDIUM
Incorrect Type Conversion or Cast (CWE-704)
2026-02-27 9b29abf9-4ab0-4765-b253-1875cd9b441e
6.5
CVSS 3.1 · NVD
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Severity by source

NVD PRIMARY
6.5 MEDIUM
AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
SUSE
MEDIUM
qualitative

Primary rating from NVD.

CVSS VectorNVD

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

Lifecycle Timeline

3
Analysis Generated
Mar 12, 2026 - 21:55 vuln.today
Patch released
Mar 03, 2026 - 20:25 nvd
Patch available
CVE Published
Feb 27, 2026 - 01:16 nvd
MEDIUM 6.5

DescriptionCVE.org

Net::CIDR versions before 0.24 for Perl mishandle leading zeros in IP CIDR addresses, which may have unspecified impact.

The functions addr2cidr and cidrlookup may return leading zeros in a CIDR string, which may in turn be parsed as octal numbers by subsequent users. In some cases an attacker may be able to leverage this to bypass access controls based on IP addresses.

The documentation advises validating untrusted CIDR strings with the cidrvalidate function. However, this mitigation is optional and not enforced by default. In practice, users may call addr2cidr or cidrlookup with untrusted input and without validation, incorrectly assuming that this is safe.

AnalysisAI

Net::CIDR versions before 0.24 for Perl mishandle leading zeros in IP CIDR addresses, which may have unspecified impact. The functions addr2cidr and cidrlookup may return leading zeros in a CIDR string, which may in turn be parsed as octal numbers by subsequent users. [CVSS 6.5 MEDIUM]

Technical ContextAI

Classified as CWE-704 (Incorrect Type Conversion or Cast). Affects Net\. Net::CIDR versions before 0.24 for Perl mishandle leading zeros in IP CIDR addresses, which may have unspecified impact.

The functions addr2cidr and cidrlookup may return leading zeros in a CIDR string, which may in turn be parsed as octal numbers by subsequent users. In some cases an attacker may be able to leverage this to bypass access controls based on IP addresses.

The documentation advises validating untrusted CIDR strings with the cidrvalidate function. However, this mitigation is

RemediationAI

A vendor patch is available — apply it immediately. Restrict network access to the affected service where possible.

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Vendor StatusVendor

SUSE

Severity: Medium
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Fixed
SUSE Linux Enterprise High Performance Computing 15 SP7 Fixed
SUSE Linux Enterprise Module for Development Tools 15 SP7 Fixed
SUSE Linux Enterprise Server 15 SP7 Fixed
SUSE Linux Enterprise Server for SAP Applications 15 SP7 Fixed

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CVE-2021-4456 vulnerability details – vuln.today

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