Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) Affecting ultravnc/UltraVNC package, versions [0,]
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published1 Jul 2026
- disclosed1 Jul 2026
- creditUnknown
Introduced: 1 Jul 2026
CVE-2026-44040 (opens in a new tab)How to fix?
There is no fixed version for ultravnc/UltraVNC.
Overview
Affected versions of this package are vulnerable to Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) due to the use of a time-seeded pseudo-random number generator in the vncRandomBytes function. An attacker can predict authentication challenge bytes by observing the authentication exchange and enumerating the limited seed space, which may allow forgery or offline brute-forcing of responses.