CVE-2026-49940
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedNet::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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe Net::CIDR::Set Perl module (versions through 0.20) fails to properly validate Unicode digit characters in IP addresses and netmasks. When Arabic-Indic or other Unicode digit variants (e.g., U+0661) are used, they are accepted but not correctly converted to their ASCII numeric equivalents during parsing, potentially allowing netmasks to be interpreted as permitting larger networks than intended.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 0.21CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check if Net::CIDR::Set is installedRun: perl -MNet::CIDR::Set -e 'print $Net::CIDR::Set::VERSION'Affected if The module is present in the Perl environment
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Determine the installed versionCompare the output version against the affected range (all versions through 0.20)Affected if Version is 0.20 or lower (less than 0.21)
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Test if Unicode digits are accepted in IP inputAttempt to create a Net::CIDR::Set object using an IP address or netmask containing Unicode digits (e.g., Arabic-Indic digits like U+0661) and observe whether it accepts the input without errorAffected if The module accepts IP addresses with non-ASCII Unicode digits without rejecting them
If Net::CIDR::Set version is below 0.21 and the system processes IP addresses containing Unicode characters, the environment is affected by this vulnerability.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped0.21
Upgrade to Net::CIDR::Set version 0.21 or later which properly normalizes Unicode digits to ASCII before parsing, or implement input validation to reject non-ASCII digit characters in IP addresses and netmasks.
Version 0.21
- Install the latest version of Net::CIDR::Set using CPAN: cpan -i Net::CIDR::Set
- Or use cpanm: cpanm Net::CIDR::Set
- Or specify version 0.21 explicitly: cpan -i Net::CIDR::[email protected]
- Verify the installed version matches 0.21 or later using: perl -MNet::CIDR::Set -e 'print $Net::CIDR::Set::VERSION'
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation6.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-49940 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-49940 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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