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windows-utilities-release EUVDEUVD-2026-34195

| CVE-2026-41858 HIGH
Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) (CWE-338)
2026-06-04 vmware GHSA-f9p6-prpf-3757
7.5
CVSS 3.1 · Vendor: vmware
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Identify BOSH-managed Windows VM exposing RDP/WinRM
  2. Delivery
    Estimate VM boot timestamp from logs or service banners
  3. Exploit
    Enumerate clock-seeded PRNG candidate passwords
  4. Execution
    Brute-force Administrator login over RDP/WinRM
  5. Persist
    Authenticate as local Administrator
  6. Impact
    Defeat randomize_password hardening control

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A04:2025 - Cryptographic Failures
ASVS 5.0
V11 - Cryptography Cryptographic PRNG selection
Exploitation Conditions

Exploitation requires that the target VM was provisioned with the windows-utilities-release randomize_password job from an affected version (pre-v0.23.0), that the attacker can reach an authentication surface that accepts the local Administrator credential (typically RDP/3389 or WinRM/5985-5986) over the network, and that the attacker can estimate the VM's boot time closely enough to reduce the PRNG seed search space to a tractable candidate list. Limiting factors: the randomize_password job must actually have been included in the deployment manifest (it is opt-in hardening, not default on every BOSH Windows VM); the local Administrator account must be reachable (deployments that block inbound RDP/WinRM at the network layer significantly raise the bar); and the attacker needs reasonably tight boot-time estimation - wider uncertainty enlarges the candidate set and may make online brute-forcing detectable or rate-limited. No special user interaction is required (UI:N) and no prior authentication is needed to attempt the recovered credential (PR:N).

Impact

The CVSS 3.1 vector AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N indicates a pure confidentiality compromise reachable over the network with no authentication or user interaction, justifying the 7.5 base score. In practice the real-world severity depends on whether an attacker can plausibly estimate boot time (for cloud-managed BOSH deployments, deployment logs, monitoring endpoints, or RDP/WinRM banner timing can leak this) and whether the recovered Administrator account is reachable from the attacker's network position - so while the rating is High, exploitation typically requires at least network adjacency to the deployed Windows VMs. EPSS and CISA KEV data were not provided in the input, so probabilistic exploitation likelihood and active-exploitation status are unknown; treat this as no public exploit identified at time of analysis. The signal mix is internally consistent: a cryptographic weakness with network-reachable impact and no integrity/availability effect, which fits a credential-recovery weakness rather than RCE.

Exploit ScenarioDerived

An attacker with network reachability to a BOSH-managed Windows VM observes or infers the VM's boot time (e.g., from monitoring dashboards, deployment pipelines, BOSH director logs, RDP/WinRM service availability, or TCP timestamp options), enumerates the small candidate seed window around that time, generates the corresponding Administrator password candidates from the known Get-RandomPassword algorithm, and tries them against RDP or WinRM. A successful guess yields local Administrator on the VM, completely defeating the randomize_password hardening control.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.0% exploitation probability (EPSS)

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AnalysisAIv3 – Jun 04, 2026

Predictable password generation in Cloud Foundry's BOSH windows-utilities-release (versions prior to v0.23.0) allows remote attackers to recover the local Administrator password set by the randomize_password job. The Get-RandomPassword routine seeds its PRNG from system clock state, so an attacker who can estimate VM boot time can reduce the search space to a small candidate list and brute-force the credential, defeating the hardening control that was supposed to lock down the account. No public exploit identified at time of analysis, but the CVSS 7.5 (AV:N/AC:L/PR:N/UI:N/C:H) reflects the realistic recoverability of high-value Administrator credentials over the network.

Earlier versions of this analysis (2)
v2 Jun 04, 2026 - 03:29 cvss changed CVSS 7.5

Administrator credential disclosure in Cloud Foundry BOSH windows-utilities-release (versions prior to v0.23.0) lets network-adjacent attackers recover the local Administrator password generated by the randomize_password job. The Get-RandomPassword routine seeds a PRNG with the clock, so an attacker who can estimate VM boot time reconstructs a tractable candidate set and defeats the hardening control entirely. No public exploit identified at time of analysis, and CVSS 7.5 (AV:N/AC:L/PR:N/UI:N) reflects unauthenticated network reachability of the resulting credential reuse.

v1 Jun 04, 2026 - 02:43 CVSS 6.5

Predictable Administrator password generation in Cloud Foundry's windows-utilities-release (all versions prior to v0.23.0) allows a remote unauthenticated attacker to recover the Windows local Administrator credential by exploiting a clock-seeded PRNG in the Get-RandomPassword function. The randomize_password job, which exists specifically as a hardening control to lock the Administrator account behind an unguessable password, is entirely defeated because the password derivation seed is based on VM boot time - a value estimable from the network. No public exploit or CISA KEV listing has been identified at time of analysis, but the CVSS:3.1/AV:N/AC:L/PR:N/UI:N vector confirms remote, unauthenticated exploitation requires no special interaction beyond boot-time estimation.

RemediationAI

Vendor-released patch: upgrade windows-utilities-release to v0.23.0 or later and redeploy any BOSH manifests that include the randomize_password job so the Administrator password is regenerated using the corrected RNG; see https://www.cloudfoundry.org/blog/cve-2026-41858-brute-forceable-windows-admin-creds/ for the official guidance. Simply upgrading the release without re-running the job leaves the previously generated weak password in place, so operators must trigger a password reset on already-deployed VMs (re-running randomize_password under the patched release, or rotating the local Administrator password out-of-band via stemcell tooling). As compensating controls until upgrade, restrict network reachability to RDP (TCP/3389) and WinRM (TCP/5985, 5986) on Windows VMs to BOSH/jumpbox subnets only, disable interactive logon for the local Administrator account where Group Policy permits (trade-off: breaks break-glass access), and tighten egress on boot-time telemetry so attackers cannot precisely estimate VM start timestamps - note that timing inference is also possible from public load balancers and monitoring dashboards, so this control is partial.

Affected VersionsENISA

windows-utilities-release 0 <0.23.0

Affected Packages

euvd windows_utilities_release fix: 0.23.0

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The vulnerability lives in the windows-utilities-release BOSH job randomize_password, distributed by the Cloud Foundry Foundation for hardening Windows stemcells in BOSH-managed deployments. The job's Get-RandomPassword PowerShell helper relies on a pseudo-random number generator seeded from a predictable, clock-derived value (a classic CWE-338, Use of Cryptographically Weak PRNG, manifestation - likely the default System.Random() rather than System.Security.Cryptography.RNGCryptoServiceProvider/RandomNumberGenerator). Because the same seed reproduces the same output sequence, anyone who can narrow the seed value - here, by estimating the moment of VM boot when the job runs - can enumerate the small set of possible passwords the function could have produced. The CPE cpe:2.3:a:cloud_foundry_foundation:windows-utilities-release confirms the affected component is the upstream BOSH release rather than Windows itself.

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Severity by source

Vendor (vmware) PRIMARY 7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Primary rating from Vendor (vmware) · only source for this CVE.

CVSS VectorVendor: vmware

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

Lifecycle Timeline

6
Patch available
Jun 04, 2026 - 04:15 EUVD
Analysis Updated
Jun 04, 2026 - 03:29 vuln.today
v3 - CVSS changed
Analysis Updated
Jun 04, 2026 - 03:29 vuln.today
v2 - CVSS changed
Severity Changed
Jun 04, 2026 - 03:22 NVD
MEDIUM HIGH
CVSS changed
Jun 04, 2026 - 03:22 NVD
6.5 (MEDIUM) 7.5 (HIGH)
CVE Published
Jun 04, 2026 - 02:10 nvd
MEDIUM 6.5

DescriptionCVE.org

Weak Randomness / Insecure Cryptographic Primitive (CWE-338) in Get-RandomPassword in BOSH-Ecosystem / windows-utilities-release allows a network attacker to estimate VM boot time and reconstruct a small candidate list to recover the Administrator password. The randomize_password job exists solely to lock the local Administrator account behind an unguessable password as a hardening control. Because the password is derived from a predictable, clock-seeded PRNG, a network attacker who can estimate VM boot time can reconstruct a small candidate list and recover the Administrator password, defeating the hardening control.

Affected versions:

  • windows-utilities-release: all versions prior to v0.23.0 (inclusive); fixed in v0.23.0 or later

Executive ViewAI

Why It Matters

A weakness in Cloud Foundry BOSH's Windows password generation leaves administrator account credentials recoverable by remote attackers, potentially compromising full infrastructure access. Organizations running vulnerable versions have no available patch and must implement interim controls immediately to protect critical systems. This vulnerability directly threatens infrastructure security and administrative account integrity.

Business Impact: High
Compensating Controls

No vendor-released patch identified at time of analysis. Interim mitigations: (1) Implement firewall rules and network segmentation to restrict remote access to affected Windows VMs; (2) Configure account lockout policies and strengthen monitoring of authentication failure events; (3) Disable or rename local Administrator accounts where operationally feasible; (4) Enforce MFA on systems requiring administrative access; (5) Evaluate BOSH configuration options to replace predictable password generation with alternative secure mechanisms.

Threat Intelligence Overview

EPSS Score
0.0%
Top 91% exploitable
Social Media
3
Sightings
Data Quality
6 sources
Confidence: High

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 0.0%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
Yes
Human Impact
High
Technical Impact
Partial

Priority Score

38
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +38
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

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