{"id":56587,"date":"2025-07-02T02:58:15","date_gmt":"2025-07-02T02:58:15","guid":{"rendered":""},"modified":"2025-08-29T05:02:00","modified_gmt":"2025-08-29T11:02:00","slug":"cve-2025-41255-unrestricted-tls-certificate-handling-in-cyberduck-and-mountain-duck","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-41255-unrestricted-tls-certificate-handling-in-cyberduck-and-mountain-duck\/","title":{"rendered":"<strong>CVE-2025-41255: Unrestricted TLS Certificate Handling in Cyberduck and Mountain Duck<\/strong>"},"content":{"rendered":"<p><strong>Overview<\/strong><\/p>\n<p>CVE-2025-41255 is a severe vulnerability that affects the popular open-source clients, Cyberduck and Mountain Duck. This vulnerability arises due to the erroneous handling of TLS certificate pinning for untrusted certificates, such as self-signed ones. The systems unnecessarily install these certificates to the Windows Certificate Store of the current user, without any restrictions, thereby opening the door to <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-32878-critical-vulnerability-in-coros-pace-3-devices-leads-to-potential-system-compromise\/\"  data-wpil-monitor-id=\"63313\">potential system<\/a> compromise or data leakage. It is critical to address this issue, given the widespread use of these two applications in <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-49132-critical-arbitrary-code-execution-vulnerability-in-pterodactyl-game-server-management-panel\/\"  data-wpil-monitor-id=\"63312\">managing cloud storage and FTP servers<\/a>.<\/p>\n<p><strong>Vulnerability Summary<\/strong><\/p>\n<p>CVE ID: CVE-2025-41255<br \/>\nSeverity: High (8.0 CVSS Score)<br \/>\nAttack Vector: Network<br \/>\nPrivileges Required: None<br \/>\nUser Interaction: None<br \/>\nImpact: <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2023-20599-unauthorized-access-to-crypto-co-processor-registers-in-asp-leading-to-potential-system-compromise\/\"  data-wpil-monitor-id=\"64246\">Potential system<\/a> compromise or data leakage<\/p>\n<p><strong>Affected Products<\/strong><\/p><div id=\"ameeb-3900658066\" class=\"ameeb-content-2 ameeb-entity-placement\"><div style=\"border-left: 4px solid #555; padding-left: 20px; margin: 48px 0; font-family: Roboto, sans-serif; color: #ffffff; line-height: 1.6; max-width: 700px;\">\r\n  <h2 style=\"margin-top: 0; font-size: 20px; font-weight: 600; display: flex; align-items: center;\">\r\n    <a href=\"https:\/\/www.ameeba.com\/chat\" style=\"display: inline-flex; align-items: center; margin-right: 8px;\">\r\n      <img decoding=\"async\" src=\"https:\/\/www.ameeba.com\/blog\/wp-content\/uploads\/2025\/10\/Best-App-icon-Ameeba.png\" alt=\"Ameeba Chat Icon\" style=\"width: 40px; height: 40px;\" \/>\r\n    <\/a>\r\n    A new way to communicate\r\n  <\/h2>\r\n\r\n  <p style=\"margin-bottom: 12px;\">\r\n    Ameeba Chat is built on encrypted identity, not personal profiles.\r\n  <\/p>\r\n\r\n  <p style=\"margin-bottom: 16px;\">\r\n    Message, call, share files, and coordinate with identities kept separate.\r\n  <\/p>\r\n\r\n  <ul style=\"list-style: none; padding-left: 0; margin-bottom: 20px;\">\r\n    <li>\u2022 Encrypted identity<\/li>\r\n    <li>\u2022 Ameeba Chat authenticates access<\/li>\r\n    <li>\u2022 Aliases and categories<\/li>\r\n    <li>\u2022 End-to-end encrypted chat, calls, and files<\/li>\r\n    <li>\u2022 Secure notes for sensitive information<\/li>\r\n  <\/ul>\r\n\r\n  <p style=\"font-style: italic; font-weight: 600; margin-bottom: 24px;\">\r\n    Private communication, rethought.\r\n  <\/p>\r\n\r\n  <div style=\"display: flex; flex-wrap: wrap; gap: 12px;\">\r\n    <a href=\"https:\/\/www.ameeba.com\/chat\/download\" style=\"background-color: #ffffff; color: #000000; padding: 10px 20px; text-decoration: none; border-radius: 6px; font-weight: 500;\">Download Ameeba Chat<\/a>\r\n    <a href=\"https:\/\/www.ameeba.com\/chat\" style=\"border: 1px solid #ffffff; color: #ffffff; padding: 10px 20px; text-decoration: none; border-radius: 6px; font-weight: 500;\">Learn More<\/a>\r\n  <\/div>\r\n<\/div>\r\n<\/div>\n<p>Product | Affected Versions<\/p>\n<p>Cyberduck | Up to 9.1.6<br \/>\nMountain Duck | Up to 4.17.5<\/p>\n<p><strong>How the Exploit Works<\/strong><\/p>\n<p>The exploit takes advantage of the improper handling of <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-6032-unverified-tls-certificate-in-podman-machine-init-command-leads-to-potential-man-in-the-middle-attack\/\"  data-wpil-monitor-id=\"64609\">TLS certificate<\/a> pinning in Cyberduck and Mountain Duck. When these applications encounter an untrusted certificate, they should reject it to maintain secure connections. However, due to this vulnerability, these applications instead <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-33075-a-critical-windows-installer-vulnerability-that-leads-to-privilege-elevation\/\"  data-wpil-monitor-id=\"72437\">install the untrusted certificate into the Windows<\/a> Certificate Store of the current user. This behavior can be exploited by an attacker, who can present a self-signed certificate to these applications. Once installed, the <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-3090-unauthenticated-remote-attack-leading-to-potential-data-leakage-and-system-compromise\/\"  data-wpil-monitor-id=\"64610\">attacker can potentially compromise the system or leak data<\/a>.<\/p>\n<p><strong>Conceptual Example Code<\/strong><\/p><div id=\"ameeb-3939967750\" class=\"ameeb-content ameeb-entity-placement\"><div class=\"poptin-embedded\" data-id=\"f6b387694f681\"><\/div>\r\n\r\n\r\n\r\n\r\n\r\n<\/div>\n<p>Below is a conceptual example of how an attacker might exploit this vulnerability:<\/p>\n<pre><code class=\"\" data-line=\"\">POST \/vulnerable\/endpoint HTTP\/1.1\nHost: target.example.com\nContent-Type: application\/x-www-form-urlencoded\ncertificate=-----BEGIN CERTIFICATE-----[malicious_certificate]-----END CERTIFICATE-----<\/code><\/pre>\n<p>In this example, the attacker sends a self-signed <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2024-31854-critical-tls-server-certificate-validation-vulnerability-in-sicam-toolbox-ii\/\"  data-wpil-monitor-id=\"70018\">certificate to the vulnerable<\/a> endpoint. The applications, instead of rejecting the certificate, install it into the Windows Certificate Store, giving the attacker the opportunity to <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-6435-firefox-vulnerability-leading-to-potential-system-compromise-and-data-leakage\/\"  data-wpil-monitor-id=\"70019\">compromise the system or leak data<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Overview CVE-2025-41255 is a severe vulnerability that affects the popular open-source clients, Cyberduck and Mountain Duck. This vulnerability arises due to the erroneous handling of TLS certificate pinning for untrusted certificates, such as self-signed ones. The systems unnecessarily install these certificates to the Windows Certificate Store of the current user, without any restrictions, thereby opening [&hellip;]<\/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,"footnotes":""},"categories":[1],"tags":[],"vendor":[82],"product":[],"attack_vector":[],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-56587","post","type-post","status-publish","format-standard","hentry","category-uncategorized","vendor-microsoft"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/56587","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/comments?post=56587"}],"version-history":[{"count":5,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/56587\/revisions"}],"predecessor-version":[{"id":65225,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/56587\/revisions\/65225"}],"wp:attachment":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/media?parent=56587"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/categories?post=56587"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/tags?post=56587"},{"taxonomy":"vendor","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/vendor?post=56587"},{"taxonomy":"product","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/product?post=56587"},{"taxonomy":"attack_vector","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/attack_vector?post=56587"},{"taxonomy":"asset_type","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/asset_type?post=56587"},{"taxonomy":"severity","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/severity?post=56587"},{"taxonomy":"exploit_status","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/exploit_status?post=56587"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}