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VulnerabilityPublished Updated

CVE-2025-51726: Weak Cryptography

Source CVE Database V5

0

Not known to be exploited · CVSS 8.4 High.

Data as of 26 Oct 2026, 09:15 UTC

CVSS 3.1 base score
8.4High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 1% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 4 Aug 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

AI-suggested

European organizations should take several specific steps to mitigate this vulnerability beyond generic patching advice. First, they should verify the integrity of CyberGhostVPNSetup.exe installers by checking for updated versions signed with stronger cryptographic hashes (e.g., SHA-256) and avoid using installers signed with SHA-1. If no updated installer is available, organizations should consider temporarily suspending deployment of this VPN client until a secure version is released. Secondly, enforce strict application whitelisting and SmartScreen policies to prevent execution of unsigned or weakly signed binaries. Third, implement endpoint protection solutions capable of detecting anomalous installer behavior and memory exploitation attempts. Fourth, conduct internal audits to identify systems running vulnerable versions and isolate or remediate them promptly. Finally, encourage users to download software only from official sources and educate them about the risks of installing unverified software. From a development perspective, CyberGhost should update their build process to use strong cryptographic signatures and enable high entropy ASLR in their binaries to harden against exploitation.

Description

CyberGhostVPNSetup.exe (Windows installer) is signed using the weak cryptographic hash algorithm SHA-1, which is vulnerable to collision attacks. This allows a malicious actor to craft a fake installer with a forged SHA-1 certificate that may still be accepted by Windows signature verification mechanisms, particularly on systems without strict SmartScreen or trust policy enforcement. Additionally, the installer lacks High Entropy Address Space Layout Randomization (ASLR), as confirmed by BinSkim (BA2015 rule) and repeated WinDbg analysis. The binary consistently loads into predictable memory ranges, increasing the success rate of memory corruption exploits. These two misconfigurations, when combined, significantly lower the bar for successful supply-chain style attacks or privilege escalation through fake installers.

References

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