{"id":64122,"date":"2025-08-17T14:39:44","date_gmt":"2025-08-17T14:39:44","guid":{"rendered":""},"modified":"2025-09-03T03:47:18","modified_gmt":"2025-09-03T09:47:18","slug":"cve-2025-55161-critical-ssrf-vulnerability-in-stirling-pdf-application","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-55161-critical-ssrf-vulnerability-in-stirling-pdf-application\/","title":{"rendered":"<strong>CVE-2025-55161: Critical SSRF Vulnerability in Stirling-PDF Application<\/strong>"},"content":{"rendered":"<p><strong>Overview<\/strong><\/p>\n<p>The CVE-2025-55161 vulnerability is a critical security flaw that has been identified in the Stirling-PDF web application. This vulnerability specifically affects the \/api\/v1\/convert\/markdown\/pdf endpoint of the Stirling-PDF application which is used to convert Markdown to PDF files. The <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-30327-integer-overflow-vulnerability-in-incopy-leading-to-potential-arbitrary-code-execution\/\"  data-wpil-monitor-id=\"73669\">vulnerability has the potential<\/a> to be heavily exploited, leading to system compromise or potential data leakage. Given the severity of the issue, it is crucial for system administrators and developers who are using the <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-52914-sql-injection-vulnerability-in-mitel-micollab-suite-applications-services\/\"  data-wpil-monitor-id=\"75684\">application to understand the nature of this vulnerability<\/a>, how it can be exploited, and the necessary steps to mitigate its potential impact.<\/p>\n<p><strong>Vulnerability Summary<\/strong><\/p>\n<p>CVE ID: CVE-2025-55161<br \/>\nSeverity: Critical (CVSS 8.6)<br \/>\nAttack Vector: Network<br \/>\nPrivileges Required: None<br \/>\nUser Interaction: None<br \/>\nImpact: <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-21432-memory-corruption-vulnerability-resulting-in-potential-system-compromise-or-data-leakage\/\"  data-wpil-monitor-id=\"75571\">System compromise or data<\/a> leakage<\/p>\n<p><strong>Affected Products<\/strong><\/p><div id=\"ameeb-636836395\" 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>Stirling-PDF | <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-55010-arbitrary-php-object-instantiation-in-kanboard-prior-to-version-1-2-47\/\"  data-wpil-monitor-id=\"77941\">Prior to version<\/a> 1.1.0<\/p>\n<p><strong>How the Exploit Works<\/strong><\/p>\n<p>The <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-47982-improper-input-validation-vulnerability-in-windows-storage-vsp-driver-leading-to-privilege-escalation\/\"  data-wpil-monitor-id=\"75570\">vulnerability exists because of an improper<\/a> sanitization mechanism while converting Markdown to PDF. The Stirling-PDF application uses a third-party tool to process this conversion and includes a sanitizer for security sanitization. However, this sanitization can be bypassed, leading to a <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-46385-severe-server-side-request-forgery-ssrf-vulnerability\/\"  data-wpil-monitor-id=\"76553\">Server-Side Request Forgery<\/a> (SSRF) vulnerability. An attacker can exploit this vulnerability to cause the server to send HTTP requests to an arbitrary destination, possibly <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-27050-memory-corruption-vulnerability-leading-to-potential-system-compromise-and-data-leakage\/\"  data-wpil-monitor-id=\"74942\">leading to system compromise or data<\/a> leakage.<\/p>\n<p><strong>Conceptual Example Code<\/strong><\/p><div id=\"ameeb-367913483\" 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<pre><code class=\"\" data-line=\"\">POST \/api\/v1\/convert\/markdown\/pdf HTTP\/1.1\nHost: vulnerable-host.example.com\nContent-Type: application\/json\n{ &quot;markdown&quot;: &quot;![](http:\/\/malicious-site.com\/ssrf-payload)&quot; }<\/code><\/pre>\n<p>In the above example, an attacker uses the Markdown image syntax to craft a malicious payload. The Stirling-PDF server will fetch the image from the URL, thereby sending a <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2024-9408-server-side-request-forgery-attack-in-eclipse-glassfish\/\"  data-wpil-monitor-id=\"77256\">request to the attacker&#8217;s server<\/a>.<\/p>\n<p><strong>Mitigation Guidance<\/strong><\/p>\n<p>Users are advised to immediately upgrade to version 1.1.0 of the <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-43588-out-of-bounds-write-vulnerability-in-substance3d-sampler-versions-5-0-and-earlier\/\"  data-wpil-monitor-id=\"73514\">Stirling-PDF<\/a> application which contains a patch for this vulnerability. If upgrading is not immediately possible, the use of a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can provide temporary mitigation by blocking or alerting on suspicious requests to the \/api\/v1\/convert\/markdown\/pdf endpoint. However, these temporary measures are not a substitute for patching the application.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Overview The CVE-2025-55161 vulnerability is a critical security flaw that has been identified in the Stirling-PDF web application. This vulnerability specifically affects the \/api\/v1\/convert\/markdown\/pdf endpoint of the Stirling-PDF application which is used to convert Markdown to PDF files. The vulnerability has the potential to be heavily exploited, leading to system compromise or potential data leakage. [&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":[],"product":[],"attack_vector":[101],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-64122","post","type-post","status-publish","format-standard","hentry","category-uncategorized","attack_vector-ssrf"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/64122","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=64122"}],"version-history":[{"count":8,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/64122\/revisions"}],"predecessor-version":[{"id":70332,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/64122\/revisions\/70332"}],"wp:attachment":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/media?parent=64122"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/categories?post=64122"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/tags?post=64122"},{"taxonomy":"vendor","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/vendor?post=64122"},{"taxonomy":"product","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/product?post=64122"},{"taxonomy":"attack_vector","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/attack_vector?post=64122"},{"taxonomy":"asset_type","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/asset_type?post=64122"},{"taxonomy":"severity","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/severity?post=64122"},{"taxonomy":"exploit_status","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/exploit_status?post=64122"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}