CVE-2026-42177— linux-entra-sso: PRT SSO cookie can leak to attacker-controlled hosts when broad host permissions are granted

linux-entra-sso: PRT SSO cookie can leak to attacker-controlled hosts when broad host permissions are granted

linux-entra-sso is a browser plugin for Linux to SSO on Microsoft Entra ID. Prior to 1.8.1, platform/chrome/js/platform-chrome.js:69-88 registers a single declarativeNetRequest rule whose urlFilter is Platform.SSO_URL + "/*", i.e. "https://login.microsoftonline.com/*". Chrome's urlFilter without a | or || anchor is substring-matched against the full request URL. The same applied rule action is modifyHeaders that attaches the Entra ID Primary Refresh Token cookie. The Firefox adapter in platform/firefox/js/platform-firefox.js:53 performs a belt-and-braces startsWith(Platform.SSO_URL) check before injecting the header; the Chrome adapter does not. When the extension holds broad host permissions through the optional_host_permissions: ["https://*/*"] declared in platform/chrome/manifest.json:34, a main-frame navigation to a URL whose path embeds https://login.microsoftonline.com/ causes Chrome to attach the PRT cookie to the request to the attacker-controlled host. This vulnerability is fixed in 1.8.1.

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

访问控制不恰当

Entra ID SSO via Microsoft Identity Broker on Linux 访问控制错误漏洞

Entra ID SSO via Microsoft Identity Broker on Linux是Siemens开源的一款Linux设备上通过微软身份代理实现单点登录的浏览器扩展。 Entra ID SSO via Microsoft Identity Broker on Linux 1.8.1之前版本存在访问控制错误漏洞，该漏洞源于Chrome适配器未正确检查URL前缀，可能导致主框架导航时附加PRT Cookie到攻击者控制的主机。

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