High [CVE-2026-18536] Predictable random numbers due to unencrypted remote entropy sources

Data::Entropy versions before 0.010 for Perl read remote entropy sources over plain HTTP. The Data::Entropy::RawSource::RandomOrg integrity check trivially matches any non-empty byte string.

Any on-path attacker, such as open WiFi, a compromised ISP, captive portal, or a hostile egress proxy substitutes the response and thereby chooses the bytes returned by rand_bits and rand_int for every application that selected one of these sources via with_entropy_source.

The _checkbuf method response is equally attacker-controlled, so the retry/sleep behaviour is steerable too. This component reads remote entropy (randomness) sources over unencrypted HTTP.

An on-path attacker, such as one on an open Wi-Fi network or a compromised internet service provider (ISP), can intercept and alter the responses from these sources. This allows the attacker to control the random bytes generated by the application, leading to predictable random numbers.

Such a compromise of cryptographic randomness can have significant security implications, potentially enabling further attacks. This Important flaw in `perl-Data-Entropy` allows an on-path attacker to manipulate random number generation by intercepting unencrypted HTTP requests to specific remote entropy sources.