CVE-2025-54883 is a critical vulnerability identified in the Vision-ui library, a set of enterprise-grade, dependency-free modules used in modern web projects developed by DavidOsipov. The flaw exists in versions 1.4.0 and below, specifically within the getSecureRandomInt function of the security-kit module (versions prior to 3.5.0) bundled with Vision-ui. The vulnerability stems from a cryptographic weakness classified under CWE-338, which involves the use of a cryptographically weak pseudo-random number generator (PRNG). The root cause is a silent 32-bit integer overflow in the internal masking logic of the function. This overflow occurs due to the use of a 32-bit bitwise left-shift operation (<<) to generate a bitmask for the rejection sampling algorithm. When the requested range for random number generation exceeds 2^32, the mask becomes incorrect, resulting in a non-uniform distribution of random numbers. This undermines the randomness quality and predictability of the output, which is critical for cryptographic operations, secure token generation, session identifiers, or any security-sensitive functionality relying on this PRNG. The issue compromises the confidentiality and integrity of systems relying on this function, as attackers could potentially predict or influence random values, leading to further exploitation such as session hijacking, cryptographic key prediction, or bypassing security controls. The vulnerability has been assigned a CVSS 4.0 score of 9.3 (critical), reflecting its network attack vector, no required privileges or user interaction, and high impact on confidentiality and integrity. The flaw is fixed in Vision-ui version 1.5.0 and security-kit 3.5.0. No known exploits are reported in the wild yet, but the severity and ease of exploitation warrant immediate attention.

For European organizations, this vulnerability poses a significant risk, especially those utilizing Vision-ui in their web applications or services. The compromised PRNG can lead to predictable cryptographic operations, undermining secure communications, authentication mechanisms, and data protection measures. This can result in unauthorized access, data breaches, and potential regulatory non-compliance under GDPR due to inadequate protection of personal data. Enterprises in finance, healthcare, government, and critical infrastructure sectors are particularly vulnerable due to the sensitive nature of their data and the high value of their targets. The flaw could facilitate advanced persistent threats (APTs) or automated attacks that exploit weak randomness to escalate privileges or exfiltrate data. Additionally, the widespread use of Vision-ui in modern web projects means that the attack surface is broad, potentially affecting numerous organizations across Europe. The lack of required authentication or user interaction lowers the barrier for attackers to exploit this remotely, increasing the urgency for mitigation.

European organizations should immediately audit their use of Vision-ui and the embedded security-kit module to identify affected versions (<=1.4.0 for Vision-ui and <3.5.0 for security-kit). The primary mitigation is to upgrade to Vision-ui version 1.5.0 or later, which contains the fix for the PRNG weakness. If upgrading is not immediately feasible, organizations should implement compensating controls such as replacing or overriding the getSecureRandomInt function with a secure PRNG implementation that supports ranges larger than 2^32 without overflow issues. Additionally, organizations should conduct thorough security testing and code reviews to ensure no other components rely on the vulnerable PRNG. Monitoring network traffic and application logs for anomalous behavior related to cryptographic operations or session management is recommended. Finally, organizations should update their incident response plans to include scenarios involving cryptographic weaknesses and ensure staff are aware of this vulnerability and its implications.