Cyber Resilience

CVE-2026-49940

Rrwo Net\ \

Published
04 June 2026
Modified
22 July 2026
CVSS Score v3.1 6.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
EPSS Score 0.0020 10th percentile
Risk Priority 50 floored blend · peak EPSS

Summary

CVE-2026-49940 is a medium-severity Improper Validation of Unsafe Equivalence in Input (CWE-1289) vulnerability in Rrwo Net\. Its CVSS base score is 6.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 10th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

Net::CIDR::Set versions through 0.20 for Perl accept non-ASCII IP addresses and netmasks. Unicode digits such as the Arabic-Indic One (U+0661) were accepted but not properly parsed as numbers. This could allow network masks to accept larger networks.

CWE(s)
CWE-1289

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-49942Same product: Rrwo Net\
CVE-2026-49941Same product: Rrwo Net\
CVE-2026-3563Shared CWE-1289
CVE-2026-45191Shared CWE-1289
CVE-2026-46644Shared CWE-1289
CVE-2026-60074Shared CWE-1289
CVE-2026-27610Shared CWE-1289
CVE-2026-45190Shared CWE-1289
CVE-2026-39972Shared CWE-1289
CVE-2024-45179Shared CWE-1289

Affected Assets

rrwo
net\
\

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V5.2.2
  • V9.1.3
  • V10.4.6
  • V2.2.2

Mitigating Controls (NIST 800-53 r5) AI

SI-10 Information Input Validation good match

SI-10 requires validity checks on information inputs, directly stopping unsafe equivalence validation failures for identifiers and references.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require proper input validation and equivalence checking to prevent this class of flaw.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect unsafe equivalence flaws but does not prevent them at design time.

A.8.26 Application security requirements partial match
prevents

Application security requirements can mandate input validation rules that prevent unsafe equivalence checks.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles include proper input validation and canonicalization to avoid unsafe equivalence.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly require correct validation of resource identifiers and equivalence checks.

References