Anki's local HTTP server is vulnerable to directory traversal attacks

Anki is a program for creating and reviewing flashcards. Prior to 25.09.3, endpoints in Anki's local HTTP server do not adequately constrain requested media and built-in data paths, allowing scripts served from shared decks, or malicious websites combined with an origin-check bypass, to read local files through directory traversal. This issue is fixed in version 25.09.3.

Anki's local HTTP server does not sufficiently validate requests

Anki is a program for creating and reviewing flashcards. Prior to 25.09.3, Anki launches a local HTTP server to serve media files and web pages for parts of its interface, but requests from other origins were not sufficiently blocked. A malicious website could potentially trigger side-effecting requests to the local server, with severity varying by browser depending on Private Network Access protections. This issue is fixed in version 25.09.3.

Anki: User scripts in iframes have access to the internal Anki API

Anki is a program for creating and reviewing flashcards. Prior to 25.09.4, Anki's webview-based pages communicate with the Rust backend using an internal localhost API, and user scripts included via iframes in the editor can access this API despite protections intended to block reviewer and editor scripts. A malicious imported card package with an embedded iframe can use exposed API methods such as getImageForOcclusion to read arbitrary files accessible to the Anki process and exfiltrate them over the network. This issue is fixed in version 25.09.4.

An reflected XSS vulnerability exists in the handling of invalid paths in the Flask server in Ankitects Anki 24.04. A specially crafted flashcard can lead to JavaScript code execution and result in an arbitrary file read. An attacker can share a malicious flashcard to trigger this vulnerability.

A blocklist bypass vulnerability exists in the LaTeX functionality of Ankitects Anki 24.04. A specially crafted malicious flashcard can lead to an arbitrary file creation at a fixed path. An attacker can share a malicious flashcard to trigger this vulnerability.

An vulnerability in the handling of Latex exists in Ankitects Anki 24.04. When Latex is sanitized to prevent unsafe commands, the verbatim package, which comes installed by default in many Latex distributions, has been overlooked. A specially crafted flashcard can lead to an arbitrary file read. An attacker can share a flashcard to trigger this vulnerability.

An arbitrary script execution vulnerability exists in the MPV functionality of Ankitects Anki 24.04. A specially crafted flashcard can lead to a arbitrary code execution. An attacker can send malicious flashcard to trigger this vulnerability.

In Ankitects Anki before 25.02.5, a crafted shared deck can place a YouTube downloader executable in the media folder, and this is executed for a YouTube link in the deck. The executable name could be youtube-dl.exe or yt-dlp.exe or yt-dlp_x86.exe.

Ankitects Anki before 25.02.5 allows a crafted shared deck on Windows to execute arbitrary commands when playing audio because of URL scheme mishandling.

In Ankitects Anki before 25.02.6, crafted sound file references could cause files to be written to arbitrary locations on Windows and Linux (media file pathnames are not necessarily relative to the media folder).

An issue was discovered in Ankitects Anki through 25.02. A crafted shared deck can result in attacker-controlled access to the internal API (even though the attacker has no knowledge of an API key) through approaches such as scripts or the SRC attribute of an IMG element. NOTE: this issue exists because of an incomplete fix for CVE-2024-32484.