GHSA-CW6H-FFMH-X6VH: GHSA-CW6H-FFMH-X6VH: Arbitrary Local File Disclosure via Same-Origin Policy Bypass in Anki Desktop

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GHSA-CW6H-FFMH-X6VH: Arbitrary Local File Disclosure via Same-Origin Policy Bypass in Anki Desktop

Vulnerability ID: GHSA-CW6H-FFMH-X6VH
CVSS Score: 6.5
Published: 2026-06-19

Anki Desktop for Windows, macOS, and Linux is vulnerable to local file disclosure and data exfiltration due to an iframe-based Same-Origin Policy (SOP) bypass. Maliciously crafted user scripts inside imported deck files run within the localhost context, bypassing security filters to query internal endpoints and read arbitrary system files.

TL;DR

User-supplied HTML and SVG files within imported Anki decks can bypass Same-Origin Policy protections inside Anki's local media server, enabling unauthenticated reads of sensitive local files and immediate out-of-band data exfiltration.

Technical Details

CWE ID: CWE-346 / CWE-22
Attack Vector: Network
CVSS Score: 6.5
Exploit Status: Proof-of-Concept Available
KEV Status: Not Listed

Affected Systems

Anki Desktop for Windows
Anki Desktop for macOS
Anki Desktop for Linux
aqt python module
aqt: <= 25.09.3 (Fixed in: 25.09.4)

Code Analysis

Commit: 8f39ce8

Harden media server with sandbox CSP and origin validation

Mitigation Strategies

Update Anki Desktop to version 25.09.4 or higher.
Do not import untrusted card packages (.apkg) from unverified third-party sources.
Utilize personal firewall solutions to restrict local Anki processes from executing anomalous outbound connections.

Remediation Steps:

Download the verified package for version 25.09.4 or above.
Run the installer to overwrite legacy file handlers and apply the server-level CSP controls.
Verify profile directories to clean up unused imported files.

References

Read the full report for GHSA-CW6H-FFMH-X6VH on our website for more details including interactive diagrams and full exploit analysis.

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