CVE-2025-62186: Ankitects Anki RCE Vulnerability

CVE-2025-62186 Overview

Ankitects Anki versions before 25.02.5 on Windows contain a URL scheme handling flaw that allows arbitrary command execution. A crafted shared deck can trigger the vulnerability when the application plays audio content. Attackers distribute malicious decks through Anki's shared deck ecosystem, where users download study material from untrusted sources. The flaw is tracked under CWE-829: Inclusion of Functionality from Untrusted Control Sphere.

Critical Impact
A malicious shared Anki deck can execute arbitrary commands on Windows systems when a user plays embedded audio, resulting in full compromise of the user's session.

Affected Products

Ankitects Anki on Windows, all versions before 25.02.5
Anki desktop application with audio playback enabled
Systems processing shared decks obtained from third-party sources

Discovery Timeline

2025-10-07 - CVE-2025-62186 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-62186

Vulnerability Analysis

The vulnerability originates in how Anki handles URL schemes when invoking the audio playback subsystem on Windows. A shared deck can embed audio references that mishandle URL parsing, causing the application to pass attacker-controlled input to an operating system handler. Windows resolves the scheme through its registered handlers, which enables command execution outside the intended media player context.

Exploitation requires user interaction limited to normal deck usage. A student reviewing cards from a downloaded deck triggers the payload when Anki attempts to play the audio associated with a card. The attacker gains code execution with the privileges of the logged-in user.

The issue falls under CWE-829, reflecting inclusion of functionality from an untrusted source. Anki's shared deck model treats community content as trusted for playback, extending the trust boundary to arbitrary URL handlers.

Root Cause

Anki did not sanitize or restrict URL schemes referenced by audio elements inside a deck package. On Windows, unfiltered scheme handling allowed a crafted URI to invoke shell execution paths instead of a bounded media loader.

Attack Vector

An attacker publishes a shared deck to a distribution channel used by Anki users, such as community deck repositories or direct file transfer. The victim imports the deck and reviews a card containing the malicious audio reference. Anki processes the audio URL, and Windows executes the attacker's commands under the current user context.

The vulnerability requires local access in the sense that the deck must be opened on the target system. No network authentication is needed on the target, and no elevated privileges are required for the attacker's payload to run.

Detection Methods for CVE-2025-62186

Indicators of Compromise

Anki processes spawning cmd.exe, powershell.exe, or other shell interpreters as child processes
Unexpected outbound network connections initiated shortly after opening a shared deck
Newly created .apkg or .colpkg files from unverified sources followed by process anomalies
Windows registry queries against URL scheme handlers immediately following Anki audio playback

Detection Strategies

Monitor process trees where anki.exe is the parent of scripting or shell binaries
Alert on file writes to user profile directories originating from Anki subprocesses
Inspect imported deck files for embedded URI schemes referencing non-media handlers
Correlate audio playback events with process creation telemetry to surface command execution

Monitoring Recommendations

Ingest Windows Sysmon Event ID 1 (process creation) into your SIEM and filter on Anki as parent process
Track deck imports through file system telemetry on user Download and Desktop directories
Baseline normal Anki behavior to identify deviations tied to malicious deck content

How to Mitigate CVE-2025-62186

Immediate Actions Required

Upgrade Anki to version 25.02.5 or later on all Windows endpoints
Audit shared decks imported from untrusted sources and quarantine suspicious files
Restrict execution of Anki to standard user contexts and enforce application allowlisting where feasible
Educate users on the risk of importing decks from unverified community sources

Patch Information

Ankitects released the fix in Anki 25.02.5. Details are available in the Anki 25.02.5 GitHub Release Notes. Administrators managing shared workstations should deploy the update through their software distribution tooling.

Workarounds

Avoid importing shared decks from unverified authors until systems are patched
Disable audio playback in Anki settings if immediate patching is not feasible
Use Windows AppLocker or WDAC to block child processes spawned by anki.exe

bash

# Verify installed Anki version on Windows via PowerShell
Get-ItemProperty HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\* |
  Where-Object { $_.DisplayName -like 'Anki*' } |
  Select-Object DisplayName, DisplayVersion