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CVE-2021-29424

25
FAUCET Score

CVE-2021-29424 describes an IP address validation vulnerability in the Perl Net::Netmask module (before version 2.0000) that allows attackers to bypass access controls by using IP address strings with extraneous leading zero characters. This high-severity vulnerability (CVSS 7.5) is easily exploitable over the network with no user interaction, potentially leading to unauthorized access. While there are no known public exploits or active exploitation, the vulnerability has garnered significant community and media attention, indicating its potential impact across various applications and languages beyond Perl, including Go, Rust, and Python.

Impacted Technologies

VendorProductVersion(s)CPE
< 2.0000CPE matchmatch criteria
cpe:2.3:a:net\:\:netmask_project:net\:\:netmask:*:*:*:*:*:perl:*:*
32CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
33CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
34CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
HIGH
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
2.00%
Probability of exploitation in next 30 days
EPSS Percentile
78.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0200 is in the 62nd percentile among its peer group of 51,506 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

blog.urth.org / 2021/03/29/security-issues-in-perl-ip-address-distros
ExploitThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/CBJVLXJSWN6DKSF5ADUEERI6M23R3GGP
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/JF4CYIZELC3NISB3RMV4OCI4GYBC557B
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/Y7JIPQAY5OZ5D3DA7INQILU7SGHTHMWB
metacpan.org / changes/distribution/Net-Netmask
Release NotesThird Party Advisory
security.netapp.com / advisory/ntap-20210604-0007
Third Party Advisory