{"id":"CVE-2026-42177","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-42177","generatedAt":"2026-10-28T07:26:13.487Z","title":"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.","description":"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.","published":"2026-05-12T18:17:24.000Z","lastModified":"2026-10-26T18:10:00.000Z","status":"Deferred","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N"},"cwe":["CWE-284","CWE-436"],"affected":[],"epss":{"score":0.00234,"percentile":0.14282,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.23%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://github.com/siemens/linux-entra-sso/security/advisories/GHSA-52rj-42vh-2rxc","source":"security-advisories@github.com"},{"url":"https://github.com/siemens/linux-entra-sso/security/advisories/GHSA-52rj-42vh-2rxc","source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-42177","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}