CVE-2026-18536
Description
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.
Statement
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. This can lead to predictable values in applications configured to use these insecure sources, compromising cryptographic randomness and potentially leading to severe security vulnerabilities.
Note that Data::Entropy has been deprecated since version 0.008. Users are advised to migrate to alternative solutions that use system sources of random data, such as Crypt::SysRandom, Crypt::URandom or Crypt::PRNG.
Mitigation
Deployments should not use the RandomOrg or RandomnumbersInfo sources, as these are flawed.
They have been removed from Data::Entropy 0.010. (There was a change to use HTTPS to connect to these sources in version 0.009 that did not work.)
Note that Data::Entropy has been deprecated since version 0.008. Users are advised to migrate to alternative solutions that use system sources of random data, such as Crypt::SysRandom, Crypt::URandom or Crypt::PRNG.
Understanding the Weakness (CWE)
Integrity,Confidentiality
Technical Impact: Read Application Data; Modify Files or Directories
Anyone can read the information by gaining access to the channel being used for communication. Many communication channels can be "sniffed" (monitored) by adversaries during data transmission. For example, in networking, packets can traverse many intermediary nodes from the source to the destination, whether across the internet, an internal network, the cloud, etc. Some actors might have privileged access to a network interface or any link along the channel, such as a router, but they might not be authorized to collect the underlying data. As a result, network traffic could be sniffed by adversaries, spilling security-critical data.
Integrity,Confidentiality
Technical Impact: Read Application Data; Modify Files or Directories; Other
When full communications are recorded or logged, such as with a packet dump, an adversary could attempt to obtain the dump long after the transmission has occurred and try to "sniff" the cleartext from the recorded communications in the dump itself. Even if the information is encoded in a way that is not human-readable, certain techniques could determine which encoding is being used, then decode the information.
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