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CVE Record

CVE-2021-30121: (Semi-)Authenticated local file inclusion in Kaseya VSA < v9.5.6

Semi-authenticated local file inclusion The contents of arbitrary files can be returned by the webserver Example request: `https://x.x.x.x/KLC/js/Kaseya.SB.JS/js.aspx?path=C:\Kaseya\WebPages\dl.asp` A valid sessionId is required but can be easily obtained via CVE-2021-30118

MediumCVSS 6.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-30121 lets a low-privileged or semi-authenticated user read arbitrary local files through the Kaseya VSA web server. The direct business risk is exposure of sensitive server-side data, configuration, or credentials. The source bundle identifies Kaseya VSA before 9.5.6, but its structured affected-product metadata is incomplete.

Executive priority

Prioritize remediation for any exposed Kaseya VSA server because the vulnerability can disclose sensitive files and may chain with a related session weakness. It is not marked KEV in the supplied data, so urgency is moderate unless exposure or suspicious logs are confirmed.

Technical view

The issue is a local file inclusion in Kaseya VSA's web interface, with CVSS 6.5 and high confidentiality impact. A valid sessionId is required, but the CVE description says it may be obtainable through CVE-2021-30118. No integrity or availability impact is claimed in the supplied CVSS vector.

Likely exposure

Organizations running internet-accessible or internally reachable Kaseya VSA versions before 9.5.6 are the likely exposure group. Risk increases where untrusted users can reach the VSA web interface or where related authentication weaknesses are present.

Exploitation context

The source bundle provides an example request pattern and notes a session requirement. KEV is false, and the provided sources do not establish active exploitation for this specific CVE. Treat exploitation status as unconfirmed from the supplied evidence.

Researcher notes

The CVE bundle lacks precise CPEs, CWE classification, and detailed vendor remediation text. The strongest grounded facts are the LFI behavior, low-privilege requirement, high confidentiality impact, VSA before 9.5.6 scope, and possible chaining with CVE-2021-30118.

Mitigation direction

  • Identify all Kaseya VSA instances and confirm their running version.
  • Upgrade Kaseya VSA to 9.5.6 or later if vendor guidance confirms applicability.
  • Restrict VSA web access to trusted administrative networks or VPN paths.
  • Review Kaseya and DIVD advisories for version-specific remediation guidance.
  • Assess whether CVE-2021-30118 affects the same environment.

Validation and detection

  • Inventory VSA servers, including externally exposed and partner-managed instances.
  • Confirm whether any instance runs a version earlier than 9.5.6.
  • Review web access logs for unusual KLC js.aspx file path requests.
  • Check for evidence of sensitive file reads or suspicious session activity.
  • Validate compensating access controls around the VSA web interface.
Prepared
Confidence
medium
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2021-30121 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
6.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
4Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
6.5CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N2.83.6Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

6.5Medium
CVSS 3.1 vector shape for CVE-2021-30121Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.