{"id":59715,"date":"2025-07-28T22:47:12","date_gmt":"2025-07-28T22:47:12","guid":{"rendered":""},"modified":"2025-09-14T12:47:45","modified_gmt":"2025-09-14T18:47:45","slug":"cve-2025-8031-leakage-of-http-basic-authentication-credentials-in-firefox-and-thunderbird","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-8031-leakage-of-http-basic-authentication-credentials-in-firefox-and-thunderbird\/","title":{"rendered":"CVE-2025-8031: Leakage of HTTP Basic Authentication Credentials in Firefox and Thunderbird<\/strong>"},"content":{"rendered":"

Overview<\/strong><\/p>\n

CVE-2025-8031 is a critical vulnerability affecting numerous versions of popular web browser Firefox and email client Thunderbird. This vulnerability arises from a flaw in the handling of URLs in CSP (Content Security Policy) reports, which can potentially lead to leakage of HTTP Basic Authentication credentials. Given the widespread use of these applications across a variety of sectors, the impact of this vulnerability<\/a> is significant. The leakage of authentication credentials can lead to unauthorized access to sensitive systems and data<\/a>, and therefore, it is of utmost importance to address this vulnerability immediately.<\/p>\n

Vulnerability Summary<\/strong><\/p>\n

CVE ID: CVE-2025-8031
\nSeverity: Critical, CVSS 9.8
\nAttack Vector: Network
\nPrivileges Required: None
\nUser Interaction: None
\nImpact: Leakage of HTTP Basic Authentication credentials, potential system compromise<\/a> or data leakage<\/p>\n

Affected Products<\/strong><\/p>\n

Product | Affected Versions<\/p>\n

Firefox | < 141\nFirefox ESR | < 128.13, < 140.1\nThunderbird | < 141, < 128.13, < 140.1\n\nHow the Exploit Works<\/strong><\/p>\n

This vulnerability arises due<\/a> to a flaw in the stripping of the `username:password` part of URLs in CSP reports. When a user accesses a site<\/a> that requires HTTP Basic Authentication, the credentials are transmitted in the HTTP header. The software fails to properly sanitize these credentials from CSP reports, potentially leaking them to third parties. An attacker could exploit this vulnerability by intercepting the CSP reports and extracting the credentials<\/a>.<\/p>\n

Conceptual Example Code<\/strong><\/p>\n

Below is a conceptual representation of how an HTTP request could look like when processed by a vulnerable system<\/a>:<\/p>\n

GET \/test\/report HTTP\/1.1\nHost: vulnerable.example.com\nAuthorization: Basic QWxhZGRpbjpPcGVuU2VzYW1l\nContent-Security-Policy-Report-Only: default-src 'self'; report-uri \/csp-report-endpoint;<\/code><\/pre>\n
In this case, the `Authorization` header contains the base64 encoded username and password (`Aladdin:OpenSesame`). The `Content-Security-Policy-Report-Only` header sets the CSP in report-only mode and specifies the endpoint (`\/csp-report-endpoint`) to which the browser should send reports about policy violation.
\nAn attacker, monitoring network traffic or having access<\/a> to the report endpoint, could intercept this request, decode the `Authorization` header, and extract the credentials.<\/p>\n
Remediation Steps<\/strong><\/p>\n
The recommended mitigation for this vulnerability is to apply the vendor patch. However, if immediate patching is not possible, implementing a Web Application Firewall (WAF) or Intrusion Detection System (IDS) could serve as a temporary mitigation, providing some level of protection against potential attacks exploiting<\/a> this vulnerability.<\/p>\n","protected":false},"excerpt":{"rendered":"
Overview CVE-2025-8031 is a critical vulnerability affecting numerous versions of popular web browser Firefox and email client Thunderbird. This vulnerability arises from a flaw in the handling of URLs in CSP (Content Security Policy) reports, which can potentially lead to leakage of HTTP Basic Authentication credentials. Given the widespread use of these applications across a […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[1],"tags":[],"vendor":[],"product":[],"attack_vector":[],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-59715","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t