CVE-2021-4456 (GCVE-0-2021-4456)

Vulnerability from cvelistv5 – Published: 2026-02-27 00:16 – Updated: 2026-02-27 16:53
VLAI
Title
Net::CIDR versions before 0.24 for Perl mishandle leading zeros in IP CIDR addresses, which may have unspecified impact
Summary
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.
Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
SSVC
Exploitation: poc Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-02-27 16:52 UTC
CWE
  • CWE-704 - Incorrect Type Conversion or Cast
Assigner
CPANSec CNA
References
Impacted products
Vendor Product Version
MRSAM Net::CIDR Affected: 0 , < 0.24 (custom)
Create a notification for this product.
Show details on NVD website
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