Network-range expansion via permissive mask parsing
Published Jun 4, 2026 · Updated Jun 4, 2026
Network mask validation bypass in Net::CIDR::Set 0.20 and earlier allows remote attackers to expand accepted network ranges. The IPv4 and IPv6 _encode routines fail to require an ASCII-decimal mask, ignoring Unicode digits or other characters and treating leading zeros as decimal. Exploitation requires a consuming application to pass attacker-controlled CIDR input and trust the resulting set, potentially admitting addresses outside the intended range.
Summary
What happened
Network mask validation bypass in Net::CIDR::Set 0.20 and earlier allows remote attackers to expand accepted network ranges. The IPv4 and IPv6 _encode routines fail to require an ASCII-decimal mask, ignoring Unicode digits or other characters and treating leading zeros as decimal. Exploitation requires a consuming application to pass attacker-controlled CIDR input and trust the resulting set, potentially admitting addresses outside the intended range.
The record
- CVE
- CVE-2026-49942
- Published
- Jun 4, 2026
- Updated
- Jun 4, 2026
- Vendor
- Robert Rothenberg
- Product
- Net::CIDR::Set
- Classifications
- CWE-1289, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 4, 2026CVE publishedPublication date reported by the CVE source.
- Jun 4, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=0 <=0.20
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
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Your stack
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