Bug 2509968 (CVE-2026-18536)

Summary: CVE-2026-18536 Data-Entropy: Data-Entropy: Predictable random numbers due to unencrypted remote entropy sources
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: high    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Data-Entropy. 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.
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Bug Depends On: 2514598, 2514600    
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Description OSIDB Bzimport 2026-08-01 11:01:07 UTC 
Data::Entropy versions before 0.010 for Perl read remote entropy sources over plain HTTP.

The Data::Entropy::RawSource::RandomOrg and Data::Entropy::RawSource::RandomnumbersInfo remote sources are accessed 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.