Cyber Resilience

CVE-2021-47155

Critical

Published: 18 March 2024

Published
18 March 2024
Modified
15 April 2026
KEV Added
Patch
CVSS Score v3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS Score 0.0005 17.3th percentile
Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-47155 is a critical-severity Improper Access Control (CWE-284) vulnerability in Urth (inferred from references). Its CVSS base score is 9.1 (Critical).

Operationally, ranked at the 17.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

The Net::IPV4Addr module 0.10 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.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

Urth
inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-284

The access control policy and procedures directly mandate and enforce proper access control mechanisms across the organization.

addresses: CWE-284

Device lock enforces restricted access until re-authentication, directly reducing unauthorized use of active sessions.

addresses: CWE-284

Supervision and review of access control activities directly detects and remediates improper access configurations or usages.

addresses: CWE-284

Explicitly identifying and documenting actions permitted without identification or authentication enforces proper access control boundaries by defining justified exceptions.

addresses: CWE-284

By automatically labeling outputs with security attributes, the control supports attribute-based enforcement and reduces exploitability of improper access control weaknesses.

addresses: CWE-284

Associating and retaining security attributes with data directly supports enforcement of access control decisions across storage, processing, and transmission.

addresses: CWE-284

Requiring prior authorization for each remote access type prevents improper access control over remote connections.

addresses: CWE-284

Requiring authorization of wireless access before allowing connections enforces proper access control for this access method.

References