Process memory exhaustion via unbounded IPv6 prefixes
Published Aug 12, 2026 · Updated Aug 12, 2026
Resource exhaustion in Net::CIDR::Set before 0.23 allows attackers to exhaust process memory via oversized IPv6 prefix lengths. The _encode method passes an unchecked prefix length to _width2bits(), which creates a proportional bitmask that _inc() expands into a Perl scalar array. Exploitation requires a caller to pass untrusted data to add() or contains(); prefixes above 128 can also create malformed set ranges that silently fail membership checks.
Summary
What happened
Resource exhaustion in Net::CIDR::Set before 0.23 allows attackers to exhaust process memory via oversized IPv6 prefix lengths. The _encode method passes an unchecked prefix length to _width2bits(), which creates a proportional bitmask that _inc() expands into a Perl scalar array. Exploitation requires a caller to pass untrusted data to add() or contains(); prefixes above 128 can also create malformed set ranges that silently fail membership checks.
The record
- CVE
- CVE-2026-19566
- Published
- Aug 12, 2026
- Updated
- Aug 12, 2026
- Vendor
- Robert Rothenberg
- Product
- Net::CIDR::Set
- Classifications
- CWE-1284, CWE-789, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 12, 2026CVE publishedPublication date reported by the CVE source.
- Aug 12, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <0.23
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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