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PatchSiren cyber security CVE debrief

CVE-2026-49940 RRWO CVE debrief

CVE-2026-49940 is a vulnerability in Net::CIDR::Set versions through 0.20 for Perl. The issue allows non-ASCII IP addresses and netmasks to be accepted but not properly parsed as numbers. This could allow network masks to accept larger networks. The vulnerability has a CVSS score of 6.5 and a severity of MEDIUM.

Vendor
RRWO
Product
Net::CIDR::Set
CVSS
MEDIUM 6.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-04
Original CVE updated
2026-07-22
Advisory published
2026-06-04
Advisory updated
2026-07-22

Who should care

Users of Net::CIDR::Set versions through 0.20 for Perl should be aware of this vulnerability and take steps to mitigate it.

Technical summary

The vulnerability is caused by the acceptance of non-ASCII IP addresses and netmasks, which are not properly parsed as numbers. This could allow network masks to accept larger networks.

Defensive priority

MEDIUM

Recommended defensive actions

  • Update to version 0.21 or later of Net::CIDR::Set
  • Use ASCII IP addresses and netmasks

Evidence notes

The vulnerability was reported by Rrwo and has been documented in the NVD.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-49940 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-49940

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-49940 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-49940

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://metacpan.org/release/RRWO/Net-CIDR-Set-0.21/changes

    9b29abf9-4ab0-4765-b253-1875cd9b441e - Release Notes

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://nvd.nist.gov/vuln/detail/CVE-2025-40911

    9b29abf9-4ab0-4765-b253-1875cd9b441e - Third Party Advisory, US Government Resource

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.