The Net::IPAddress::Util module before 5.000 for Perl does not properly consider extraneous zero characters in an IP address string, which (in some situations) allows attackers to bypass access control that is based on IP addresses.
CVE-2021-47156
MEDIUMNVD 6.56.5—
EchelonGraph scoreMEDIUM confidence
Score 6.5 from GitHub Security Advisory published 2024-03-18. NVD baseline CVSS 6.5; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
6.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.5Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 6.5
- EG Score
- 6.5(medium)
- EPSS
- 36.4%
- KEV
- Not listed
Published
March 18, 2024
Last Modified
April 15, 2026
References (6)
- cve@mitrehttps://blog.urth.org/2021/03/29/security-issues-in-perl-ip-address-distros/
- cve@mitrehttps://metacpan.org/release/Net-IPAddress-Util
- cve@mitrehttps://metacpan.org/release/PWBENNETT/Net-IPAddress-Util-5.000/changes
- af854a3a-2127-422b-91ae-364da2661108https://blog.urth.org/2021/03/29/security-issues-in-perl-ip-address-distros/
- af854a3a-2127-422b-91ae-364da2661108https://metacpan.org/release/Net-IPAddress-Util
- af854a3a-2127-422b-91ae-364da2661108https://metacpan.org/release/PWBENNETT/Net-IPAddress-Util-5.000/changes
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Frequently asked(5)
What is CVE-2021-47156?
CVE-2021-47156 is a medium vulnerability published on March 18, 2024. The Net::IPAddress::Util module before 5.000 for Perl does not properly consider extraneous zero characters in an IP address string, which (in some situations) allows attackers to bypass access control that is based on IP addresses.
When was CVE-2021-47156 disclosed?
CVE-2021-47156 was first published in the National Vulnerability Database on March 18, 2024, with the most recent update on April 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-47156 actively exploited?
CVE-2021-47156 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 36.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-47156?
CVE-2021-47156 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2021-47156?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-47156, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2021-47156
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