CVE-2021-29424

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.8% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-04-06 · updated 2026-06-17
Weakness: CWE-704

Description

The Net::Netmask module before 2.0000 for Perl does not properly consider extraneous zero characters at the beginning of an IP address string, which (in some situations) allows attackers to bypass access control that is based on IP addresses.

Affected products

Fedoraproject Fedora: 32, 33, 34
Net::Netmask Project Net::Netmask: before 2.0000 — fixed in 2.0000

How to fix

Upgrade to a fixed version: Net::Netmask Project Net::Netmask 2.0000. Check the vendor advisory for mitigations.

References

https://blog.urth.org/2021/03/29/security-issues-in-perl-ip-address-distros/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CBJVLXJSWN6DKSF5ADUEERI6M23R3GGP/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JF4CYIZELC3NISB3RMV4OCI4GYBC557B/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Y7JIPQAY5OZ5D3DA7INQILU7SGHTHMWB/
https://metacpan.org/changes/distribution/Net-Netmask#L11-22
https://security.netapp.com/advisory/ntap-20210604-0007/
https://blog.urth.org/2021/03/29/security-issues-in-perl-ip-address-distros/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CBJVLXJSWN6DKSF5ADUEERI6M23R3GGP/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JF4CYIZELC3NISB3RMV4OCI4GYBC557B/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Y7JIPQAY5OZ5D3DA7INQILU7SGHTHMWB/
https://metacpan.org/changes/distribution/Net-Netmask#L11-22
https://security.netapp.com/advisory/ntap-20210604-0007/

Get alerted when CVE-2021-29424 or the next vulnerability affects your stack