CVE-2026-86287: Net::IP::LPM versions before 1.12 for Perl accept malformed prefix lengths

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-07 · updated 2026-09-08
Weakness: CWE-1287

Description

Net::IP::LPM versions before 1.12 for Perl accept malformed prefix lengths. Non-numeric and non-ASCII prefix lengths are accepted and treated as 0. Integers over 31 bits are silently truncated. A single malformed mask will poison the lookup table. The result is that the lookup will silently succeed for every address. An allow-list will allow every address, and a deny-list will block every address.

References

https://github.com/robrwo/perl-Net-IP-LPM/commit/814f8baa85537827db8c3b3d251e48db7aca318f.patch
https://metacpan.org/release/RRWO/Net-IP-LPM-1.12/changes
http://www.openwall.com/lists/oss-security/2026/09/07/1

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