CVE-2026-39031

Deferred Deferred - Pending Action

Hardcoded RC4 Key Encryption in Lansweeper lsrunase and lsencrypt

Publication date: 2026-06-26

Last updated on: 2026-06-29

Assigner: MITRE

Description

Lansweeper lsrunase 2.0 and lsencrypt 2.0 use RC4 encryption with a hardcoded 142-byte static key array to encrypt credentials. An 8-character prefix is stored in cleartext alongside the ciphertext. This allows an attacker with local access to recover any encrypted password to plaintext using a single SHA-1 hash and RC4 decryption operation, with no brute force required.

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Meta Information

Published

2026-06-26

Last Modified

2026-06-29

Generated

2026-07-17

AI Q&A

2026-06-27

EPSS Evaluated

2026-07-15

NVD

CVE-2026-39031

Affected Vendors & Products

Vendor	Product	Version / Range
lansweeper	lsrunase	2.0
lansweeper	lsencrypt	2.0

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-321	The product uses a hard-coded, unchangeable cryptographic key.

Attack-Flow Graph

Executive Summary

This vulnerability affects Lansweeper lsrunase 2.0 and lsencrypt 2.0, which use RC4 encryption with a hardcoded 142-byte static key array to encrypt credentials.

An 8-character prefix is stored in cleartext alongside the ciphertext, which allows an attacker with local access to recover any encrypted password to plaintext.

The recovery requires only a single SHA-1 hash and RC4 decryption operation, with no brute force needed.

Impact Analysis

An attacker with local access can recover encrypted passwords in plaintext without needing to perform brute force attacks.

This compromises the confidentiality of stored credentials, potentially allowing unauthorized access to systems or data protected by those credentials.

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