CVE-2026-41887— Flarum: Path traversal in LESS parser via theme color settings (incomplete fix for CVE-2023-27577)

Flarum: Path traversal in LESS parser via theme color settings (incomplete fix for CVE-2023-27577)

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.

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

对路径名的限制不恰当(路径遍历)

Flarum 路径遍历漏洞

Flarum是Flarum开源的一个用于构建社区的简单论坛软件。 Flarum 1.8.16之前版本和2.0.0-rc.1之前版本存在路径遍历漏洞，该漏洞源于对LESS配置变量值未进行限制，可能导致任意文件包含或服务端请求伪造。

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