Vulnerability-Lookup

CVE-2026-19566 (GCVE-0-2026-19566)

Vulnerability from cvelistv5 – Published: 2026-08-12 08:39 – Updated: 2026-08-12 19:49

Title

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

Summary

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.

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-12 19:49 UTC

CWE

CWE-1284 - Improper Validation of Specified Quantity in Input
CWE-789 - Memory Allocation with Excessive Size Value

Assigner

CPANSec

References

4 references

URL	Tags
https://github.com/robrwo/perl-Net-CIDR-Set/secur…	vendor-advisory
https://github.com/robrwo/perl-Net-CIDR-Set/commi…	patch
https://metacpan.org/release/RRWO/Net-CIDR-Set-0.…	release-notes
https://www.cve.org/CVERecord?id=CVE-2026-49942	related

Impacted products

1 product

Vendor	Product	Version
RRWO	Net::CIDR::Set	Affected: 0 , < 0.23 (custom)

Show details on NVD website

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

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CVE-2026-19566 (GCVE-0-2026-19566)

Tags

Sightings

Nomenclature