CVE-2026-39031 json
Lansweeper lsrunase 2.0 and lsencrypt 2.0 use RC4 encryption with a hardcoded 142-byte static key array to encrypt credentials.
published 2026-06-26 4 mo ago modified 2026-06-29 4 mo ago also EUVD-2026-39939
- cvss
- 5.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.1%
- EPSS 0.1% chance of exploitation in 30 days, percentile 0%
- public exploits
- 0
- none known
Summary
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.
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- partial
- Assessed
- 4 mo ago
Exploit prediction
0.09% chance of exploitation in the next 30 days, higher than 0% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- usermode.net https://usermode.net/cve/lansweeper_lsrunase2_lsencrypt2_cve.pdf referenced PoC, tagged "exploit" by a source, unverified
- github.com https://github.com/user6400/cve-2026-39031-lansweeper-lsrunase2-lsencrypt2 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CISA ADP | 3.1 | 5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N |
| CNA | 3.1 | 5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N |
Classification
- Weakness
-
- CWE-321 Use of Hard-coded Cryptographic Key
References
Sources
- CVE List CVE-2026-39031
- NVD CVE-2026-39031
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