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CVE Record

CVE-2021-44426: An issue was discovered in AnyDesk before 6.2.6 and 6.3.x before 6.3.5.

An issue was discovered in AnyDesk before 6.2.6 and 6.3.x before 6.3.5. An upload of an arbitrary file to a victim's local ~/Downloads/ directory is possible if the victim is using the AnyDesk Windows client to connect to a remote machine, if an attacker is also connected remotely with AnyDesk to the same remote machine. The upload is done without any approval or action taken by the victim.

UnknownCVSS not scoredNot KEV-listedUpdated
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Security readout for executives and security teams

Plain-English summary

This AnyDesk issue lets another AnyDesk user connected to the same remote machine place a file in the Windows victim’s local Downloads folder without approval. The cited record does not show code execution, active exploitation, or a CVSS score, but unauthorized file placement can create business risk during remote-support workflows.

Executive priority

Prioritize remediation for teams using AnyDesk for shared support or administration. This is not documented as actively exploited in the provided sources, but affected remote-access tooling can create trust and endpoint-risk issues if left outdated.

Technical view

CVE-2021-44426 affects AnyDesk before 6.2.6 and 6.3.x before 6.3.5. When a victim uses the Windows client to connect to a remote machine, another AnyDesk user also connected to that remote machine can upload an arbitrary file into the victim’s local Downloads directory without victim action.

Likely exposure

Exposure is most likely where Windows users run older AnyDesk clients and connect to remote machines that may also be reachable by untrusted or less-trusted AnyDesk users.

Exploitation context

The source bundle does not cite KEV listing, active exploitation, public weaponization, or exploit code. The described scenario requires the victim and attacker to be simultaneously connected through AnyDesk to the same remote machine.

Researcher notes

The record names only the Windows client and fixed version thresholds. No CWE, CVSS vector, patch advisory details, or exploit telemetry are provided in the bundle. Avoid assuming broader platform impact or execution impact without vendor or researcher evidence.

Mitigation direction

  • Upgrade AnyDesk Windows clients to 6.2.6, 6.3.5, or later.
  • Check AnyDesk’s current vendor guidance and supported downloads.
  • Restrict who can connect to shared remote machines.
  • Review remote-support workflows involving multiple simultaneous AnyDesk users.
  • Educate users to distrust unexpected files in Downloads after remote sessions.

Validation and detection

  • Inventory AnyDesk Windows client versions across managed endpoints.
  • Flag clients older than 6.2.6 or 6.3.5.
  • Review AnyDesk usage for shared remote-machine sessions.
  • Inspect affected users’ Downloads folders for unexpected files near session times.
  • Confirm upgraded clients report fixed or later versions.
Prepared
Confidence
medium
Sources
4

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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description · low confidence lookup

File access behavior lookup

The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

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cve · low confidence lookup

CVE-2021-44426 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
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.

0CVSS vectors
0Timeline events
0ADP providers
3Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

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.