How severe is CVE-2021-30116?

CVE-2021-30116 has a CVSS score of 10/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-30116?

Affected package information for CVE-2021-30116 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2021-30116?

No fixed version has been published for CVE-2021-30116 yet. Monitor the advisory for updates, apply mitigations recommended by the vendor, and use O3 Security to track when a fix becomes available in your stack.

Is CVE-2021-30116 actively exploited in the wild?

Yes. There are 3 known exploit references for CVE-2021-30116, including 3 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2021-30116?

CVE-2021-30116 has an EPSS (Exploit Prediction Scoring System) score of 54.1%, placing it in the 98th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2021-30116 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2021-30116 (Kaseya Virtual System/Server Administrator (VSA) Information Disclosure Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2021-11-03. CISA required all US federal civilian agencies to remediate this vulnerability by 2021-11-17. The required action was: Apply updates per vendor instructions. This CVE has been used in known ransomware campaigns. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2021-30116?

CVE-2021-30116 is classified as CWE-522 (CWE-522). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Which products and versions are affected by CVE-2021-30116?

CVE-2021-30116 affects kaseya vsa agent; kaseya vsa server. Check the affected-products list on this page against your deployed version to confirm exposure.

Is there exploit tooling available for CVE-2021-30116?

A Nuclei detection template exists for CVE-2021-30116, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2021-30116 published, and has it been updated?

CVE-2021-30116 was published on July 9, 2021 and was last updated on November 10, 2025. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CISA KEV·Added 2021-11-03 — agencies required to remediate by 2021-11-17 · Ransomware

CVE-2021-30116

CRITICAL

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…

Published

Jul 9, 2021

Updated

Nov 10, 2025

Affected

0 pkgs

Patched

None yet

Exploits

3 known

EPSS Exploitation Probability

via FIRST.org ↗

54.1%probability of exploitation in next 30 days

High Risk98th percentile0.00%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

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.

Affected Products

2 products · 2 configurations

Application

vsa agentkaseya

< 9.5.0.24

range

Application

vsa serverkaseya

< 9.5.7a

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Kaseya VSA before 9.5.7 allows credential disclosure, as exploited in th…

nvd.nist.govNVDAug 2021

Kaseya VSA before 9.5.7 allows credential disclosure, as exploited in th…

cisa.govCISANov 2021

Kaseya VSA before 9.5.7 allows credential disclosure, as exploited in th…

secpod.comNVDJul 2024

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2021-30116 in your stack?

O3 detects CVE-2021-30116 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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