Framework

Flarum is open-source forum software. Prior to versions 1.8.16 and 2.0.0-rc.1, Flarum's patch for CVE-2023-27577 restricted the @import and data-uri() LESS features in the custom_less setting, but the same restriction was never applied to other settings registered as LESS config variables (for example theme_primary_color and theme_secondary_color, as well as any key registered via Extend\Settings::registerLessConfigVar()). Those values are interpolated verbatim into the LESS source at compile time, allowing an authenticated administrator to craft a theme-color value that injects an arbitrary @import directive into the compiled forum.css. Because the underlying LESS parser honours @import (inline) '<path>', an attacker can read arbitrary files reachable by the PHP process (local file inclusion) or trigger outbound HTTP(S) requests (server-side request forgery). This issue has been patched in versions 1.8.16 and 2.0.0-rc.1.

Published: 2026-05-08T15:50:38.484Z
Updated: 2026-05-08T19:26:53.642Z

Flarum is open-source forum software. A session hijacking vulnerability exists in versions prior to 1.8.10 when an attacker-controlled authoritative subdomain under a parent domain (e.g., `subdomain.host.com`) sets cookies scoped to the parent domain (`.host.com`). This allows session token replacement for applications hosted on sibling subdomains (e.g., `community.host.com`) if session tokens aren't rotated post-authentication. Key Constraints are that the attacker must control any subdomain under the parent domain (e.g., `evil.host.com` or `x.y.host.com`), and the parent domain must not be on the Public Suffix List. Due to non-existent session token rotation after authenticating we can theoretically reproduce the vulnerability by using browser dev tools, but due to the browser's security measures this does not seem to be exploitable as described. Version 1.8.10 contains a patch for the issue.

Published: 2025-03-12T14:00:21.862Z
Updated: 2025-03-12T15:29:21.831Z

Flarum is open source discussion platform software. Prior to version 1.8.5, the Flarum `/logout` route includes a redirect parameter that allows any third party to redirect users from a (trusted) domain of the Flarum installation to redirect to any link. For logged-in users, the logout must be confirmed. Guests are immediately redirected. This could be used by spammers to redirect to a web address using a trusted domain of a running Flarum installation. The vulnerability has been fixed and published as flarum/core v1.8.5. As a workaround, some extensions modifying the logout route can remedy this issue if their implementation is safe.

Published: 2024-01-05T21:02:56.513Z
Updated: 2025-06-03T14:40:49.162Z

Flarum is an open source forum software. Flarum is affected by a vulnerability that allows an attacker to conduct a Blind Server-Side Request Forgery (SSRF) attack or disclose any file on the server, even with a basic user account on any Flarum forum. By uploading a file containing a URL and spoofing the MIME type, an attacker can manipulate the application to execute unintended actions. The vulnerability is due to the behavior of the `intervention/image` package, which attempts to interpret the supplied file contents as a URL, which then fetches its contents. This allows an attacker to exploit the vulnerability to perform SSRF attacks, disclose local file contents, or conduct a blind oracle attack. This has been patched in Flarum version 1.8.0. Users are advised to upgrade. Users unable to upgrade may disable PHP's `allow_url_fopen` which will prevent the fetching of external files via URLs as a temporary workaround for the SSRF aspect of the vulnerability.

Published: 2023-08-16T20:34:11.445Z
Updated: 2024-10-02T16:00:40.870Z

flarum is a forum software package for building communities. In versions prior to 1.7.0 an admin account which has already been compromised by an attacker may use a vulnerability in the `LESS` parser which can be exploited to read sensitive files on the server through the use of path traversal techniques. An attacker can achieve this by providing an absolute path to a sensitive file in the custom `LESS` setting, which the `LESS` parser will then read. For example, an attacker could use the following code to read the contents of the `/etc/passwd` file on a linux machine. The scope of what files are vulnerable will depend on the permissions given to the running flarum process. The vulnerability has been addressed in version `1.7`. Users should upgrade to this version to mitigate the vulnerability. Users unable to upgrade may mitigate the vulnerability by ensuring that their admin accounts are secured with strong passwords and follow other best practices for account security. Additionally, users can limit the exposure of sensitive files on the server by implementing appropriate file permissions and access controls at the operating system level.

Published: 2023-03-10T20:56:58.989Z
Updated: 2025-02-25T14:58:55.839Z