Description
Net::CIDR::Set versions before 0.23 for Perl allow memory exhaustion and malformed set ranges via unbounded IPv6 prefix lengths.

The _encode method accepts any prefix length matching `(0|[1-9][0-9]*)` and passes it to _width2bits(), which builds the mask as `'1' x ($width + 8)`, one character per bit. The _inc() method then unpacks the packed mask into a Perl array of one scalar per byte, so the prefix length alone sets the allocation size: `::/100000000` builds a 100 MB string and a 12.5 million element array. The value being tested is parsed, not just the configured ranges: contains() builds a set from its argument, and _guess_coder() tries the IPv4 coder and then the IPv6 coder, so an IPv4-only set expands an oversized IPv6 prefix length before the mixed address width check rejects it.

Any caller that passes untrusted input to contains() or add() can exhaust process memory. A prefix length above 128 is also stored as a range that does not match the requested block: 2001:db8::/129 stringifies back unchanged, contains() of its own base address returns false, and removing it from a set drops the base address while the set still prints as covering it.
Published: 2026-08-12
Score: 7.5 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
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Remediation

Vendor Solution

Upgrade to Net::CIDR::Set version 0.23 or later.

Vendor Workaround

For deployments that cannot upgrade, apply the patch.

Tracking

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Advisories

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History

Wed, 12 Aug 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Wed, 12 Aug 2026 17:00:00 +0000

Type Values Removed Values Added
First Time appeared Rrwo
Rrwo net::cidr::set
Vendors & Products Rrwo
Rrwo net::cidr::set

Wed, 12 Aug 2026 08:45:00 +0000

Type Values Removed Values Added
Description Net::CIDR::Set versions before 0.23 for Perl allow memory exhaustion and malformed set ranges via unbounded IPv6 prefix lengths. The _encode method accepts any prefix length matching `(0|[1-9][0-9]*)` and passes it to _width2bits(), which builds the mask as `'1' x ($width + 8)`, one character per bit. The _inc() method then unpacks the packed mask into a Perl array of one scalar per byte, so the prefix length alone sets the allocation size: `::/100000000` builds a 100 MB string and a 12.5 million element array. The value being tested is parsed, not just the configured ranges: contains() builds a set from its argument, and _guess_coder() tries the IPv4 coder and then the IPv6 coder, so an IPv4-only set expands an oversized IPv6 prefix length before the mixed address width check rejects it. Any caller that passes untrusted input to contains() or add() can exhaust process memory. A prefix length above 128 is also stored as a range that does not match the requested block: 2001:db8::/129 stringifies back unchanged, contains() of its own base address returns false, and removing it from a set drops the base address while the set still prints as covering it.
Title Net::CIDR::Set versions before 0.23 for Perl allow memory exhaustion and malformed set ranges via unbounded IPv6 prefix lengths
Weaknesses CWE-1284
CWE-789
References

Subscriptions

Rrwo Net::cidr::set
cve-icon MITRE

Status: PUBLISHED

Assigner: CPANSec

Published:

Updated: 2026-08-12T19:49:32.903Z

Reserved: 2026-08-11T18:53:07.963Z

Link: CVE-2026-19566

cve-icon Vulnrichment

Updated: 2026-08-12T19:49:30.358Z

cve-icon NVD

Status : Received

Published: 2026-08-12T09:17:29.753

Modified: 2026-08-12T20:17:42.500

Link: CVE-2026-19566

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-12T23:00:05Z

Weaknesses
  • CWE-1284

    Improper Validation of Specified Quantity in Input

  • CWE-789

    Memory Allocation with Excessive Size Value