CVE-2025-54883 is a critical vulnerability identified in the Vision-ui product by DavidOsipov, specifically affecting versions 1.4.0 and below. Vision-ui is a set of enterprise-grade, dependency-free modules designed for modern web projects. The vulnerability resides in the getSecureRandomInt function within the security-kit component (versions prior to 3.5.0), which is bundled in Vision-ui versions up to 1.4.0. The root cause is a cryptographic weakness stemming from a 32-bit integer overflow in the internal masking logic used for rejection sampling. This overflow occurs because the function uses a 32-bit bitwise left-shift operation (<<) to generate a bitmask. When the requested random integer range exceeds 2^32, the mask calculation becomes incorrect, leading to a non-uniform distribution of random numbers. This weakens the cryptographic strength of the pseudo-random number generator (PRNG), classified under CWE-338 (Use of Cryptographically Weak PRNG). The consequence is that the random numbers generated may be predictable or biased, undermining any security mechanisms relying on this function for randomness, such as token generation, cryptographic keys, or session identifiers. The vulnerability does not require authentication, user interaction, or privileges to exploit and has a CVSS 4.0 score of 9.3 (critical), reflecting its high impact on confidentiality and integrity, with network attack vector and low attack complexity. The issue is resolved in Vision-ui version 1.5.0, where the masking logic is corrected to handle ranges larger than 2^32 properly, restoring uniform random distribution.

For European organizations using Vision-ui versions 1.4.0 or earlier, this vulnerability poses a significant risk. Since Vision-ui targets enterprise web projects, affected systems may include web applications, internal tools, or customer-facing portals that rely on secure random number generation for cryptographic operations. Exploitation could lead to predictable cryptographic tokens, session hijacking, or bypassing security controls that depend on randomness, potentially resulting in data breaches, unauthorized access, or fraud. The vulnerability's network accessibility and lack of required authentication increase the risk of remote exploitation. Given the critical severity, organizations could face compliance issues under GDPR if personal data confidentiality or integrity is compromised. Additionally, the flaw could undermine trust in digital services and cause operational disruptions if exploited. Although no known exploits are reported in the wild yet, the high CVSS score and the fundamental nature of the weakness suggest that attackers may develop exploits rapidly once the vulnerability becomes widely known.

European organizations should immediately audit their software inventories to identify any use of Vision-ui versions 1.4.0 or below, especially those incorporating the security-kit module prior to version 3.5.0. The primary mitigation is to upgrade Vision-ui to version 1.5.0 or later, where the vulnerability is fixed. If immediate upgrade is not feasible, organizations should consider implementing compensating controls such as restricting network exposure of affected applications, applying strict access controls, and monitoring for anomalous activities related to token generation or authentication processes. Developers should review any custom cryptographic or random number generation code to ensure it does not rely on the vulnerable function. Additionally, penetration testing and code audits focusing on cryptographic implementations can help identify exploitation attempts or residual weaknesses. Organizations should also maintain up-to-date threat intelligence feeds to detect emerging exploits targeting this vulnerability.