CVE Catalog

CVE-2026-42177

MediumCVSS 5.3
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.23%

14th percentile - higher than 14% of all known CVEs

Summary

In linux-entra-sso prior to 1.8.1, the Chrome adapter registers a declarativeNetRequest rule with urlFilter "https://login.microsoftonline.com/*", which without an anchor is substring-matched against the full request URL, and the modifyHeaders action attaches the Entra ID Primary Refresh Token cookie. When the extension holds broad host permissions (optional_host_permissions "https://*/*"), a main-frame navigation to a URL whose path embeds https://login.microsoftonline.com/ causes the PRT cookie to be attached to the request to an attacker-controlled host.

Risk Assessment

An attacker may capture the Primary Refresh Token cookie, potentially leading to session hijacking and escalation of access to Microsoft Entra ID resources.

Recommendation

Update linux-entra-sso to version 1.8.1 or later and consider restricting the extension's broad host permissions.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS