# CVE-2021-30116: Unauthenticated credential leak and business logic flaw in Kaseya VSA <= v9.5.6

> CVE-2021-30116: Unauthenticated credential leak and business logic flaw in Kaseya VSA <= v9.5.6. CVSS 10.0 (CVSS 3.1), in CISA KEV.

Canonical: https://rewindex.com/cve/CVE-2021-30116
Last updated: 2026-08-14T03:55:30Z

- Published: 2021-07-09 00:00 UTC · Updated: 2026-08-14 03:55 UTC · Assigner: mitre
- CVSS: 10.0 (CVSS 3.1) · Severity: Critical · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- EPSS: 85.7%, 100th percentile (scored 2026-10-25)
- CISA KEV: yes, added 2021-11-03, federal due date 2021-11-17, ransomware use: Known

## Description

Kaseya VSA before 9.5.7 allows credential disclosure, as exploited in the wild in July 2021. By default Kaseya VSA on premise offers a download page where the clients for the installation can be downloaded. The default URL for this page is https://x.x.x.x/dl.asp When an attacker download a client for Windows and installs it, the file KaseyaD.ini is generated (C:\\Program Files (x86)\\Kaseya\\XXXXXXXXXX\\KaseyaD.ini) which contains an Agent\_Guid and AgentPassword This Agent\_Guid and AgentPassword can be used to log in on dl.asp (https://x.x.x.x/dl.asp?un=840997037507813&pw=113cc622839a4077a84837485ced6b93e440bf66d44057713cb2f95e503a06d9) This request authenticates the client and returns a sessionId cookie that can be used in subsequent attacks to bypass authentication. Security issues discovered --- \* Unauthenticated download page leaks credentials \* Credentials of agent software can be used to obtain a sessionId (cookie) that can be used for services not intended for use by agents \* dl.asp accepts credentials via a GET request \* Access to KaseyaD.ini gives an attacker access to sufficient information to penetrate the Kaseya installation and its clients. Impact --- Via the page /dl.asp enough information can be obtained to give an attacker a sessionId that can be used to execute further (semi-authenticated) attacks against the system.

## CISA required action

Apply updates per vendor instructions.

## Affected vendors and products

- Kaseya: Virtual System/Server Administrator (VSA)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2021-30116)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2021-30116)
- [https://csirt.divd.nl/2021/07/04/Kaseya-Case-Update-2/](https://csirt.divd.nl/2021/07/04/Kaseya-Case-Update-2/)
- [https://csirt.divd.nl/2021/07/07/Kaseya-Limited-Disclosure/](https://csirt.divd.nl/2021/07/07/Kaseya-Limited-Disclosure/)
- [https://helpdesk.kaseya.com/hc/en-gb/articles/4403440684689-Important-Notice-July-2nd-2021](https://helpdesk.kaseya.com/hc/en-gb/articles/4403440684689-Important-Notice-July-2nd-2021)
- [https://www.secpod.com/blog/kaseya-vsa-zero-day-by-revil/](https://www.secpod.com/blog/kaseya-vsa-zero-day-by-revil/)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2021-30116 · Markdown: https://rewindex.com/cve/CVE-2021-30116.md · JSON: https://rewindex.com/api/v1/cves/CVE-2021-30116 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T03:12:18.499Z