{"id":86068,"date":"2025-12-18T07:29:48","date_gmt":"2025-12-18T07:29:48","guid":{"rendered":""},"modified":"-0001-11-30T00:00:00","modified_gmt":"-0001-11-30T06:00:00","slug":"cve-2023-49550-denial-of-service-vulnerability-in-cesanta-mjs-2-20-0","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2023-49550-denial-of-service-vulnerability-in-cesanta-mjs-2-20-0\/","title":{"rendered":"<strong>CVE-2023-49550: Denial of Service Vulnerability in Cesanta mjs 2.20.0<\/strong>"},"content":{"rendered":"<p><strong>Overview<\/strong><\/p>\n<p>A significant cybersecurity vulnerability has been identified in Cesanta mjs 2.20.0, a popular JavaScript engine for embedded systems. This vulnerability, designated as CVE-2023-49550, allows a remote attacker to cause a denial of service, potentially leading to system compromise or data leakage. Given the widespread use of Cesanta mjs in embedded systems, it is critical to understand this vulnerability and implement appropriate mitigation strategies.<\/p>\n<p><strong>Vulnerability Summary<\/strong><\/p>\n<p>CVE ID: CVE-2023-49550<br \/>\nSeverity: High (CVSS: 7.5)<br \/>\nAttack Vector: Network<br \/>\nPrivileges Required: None<br \/>\nUser Interaction: None<br \/>\nImpact: A successful exploit may lead to system compromise or data leakage.<\/p>\n<p><strong>Affected Products<\/strong><\/p><div id=\"ameeb-229674051\" 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>Cesanta mjs | 2.20.0<\/p>\n<p><strong>How the Exploit Works<\/strong><\/p>\n<p>The vulnerability resides in the mjs+0x4ec508 component of Cesanta mjs 2.20.0. A remote attacker can exploit this vulnerability by sending specially crafted data to the affected system. Upon successful exploitation, the system enters a denial-of-service state, potentially compromising the system and resulting in data leakage.<\/p>\n<p><strong>Conceptual Example Code<\/strong><\/p><div id=\"ameeb-3792465102\" 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>An example of how this vulnerability might be exploited is presented below. This is a simplified representation and may not represent actual exploit code.<\/p>\n<pre><code class=\"\" data-line=\"\">POST \/mjs+0x4ec508 HTTP\/1.1\nHost: target.example.com\nContent-Type: application\/json\n{ &quot;exploit_data&quot;: &quot;specially crafted data&quot; }<\/code><\/pre>\n<p>In this example, the attacker sends a POST request to the mjs+0x4ec508 endpoint with specially crafted data in the payload. If the exploit is successful, the system would enter a denial-of-service state.<\/p>\n<p><strong>Mitigation Guidance<\/strong><\/p>\n<p>Users of Cesanta mjs 2.20.0 should apply the vendor-supplied patch to rectify this vulnerability as soon as possible. As a temporary mitigation measure, users may also consider deploying a Web Application Firewall (WAF) or Intrusion Detection System (IDS) to detect and prevent potential exploit attempts.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Overview A significant cybersecurity vulnerability has been identified in Cesanta mjs 2.20.0, a popular JavaScript engine for embedded systems. This vulnerability, designated as CVE-2023-49550, allows a remote attacker to cause a denial of service, potentially leading to system compromise or data leakage. Given the widespread use of Cesanta mjs in embedded systems, it is critical [&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":[],"tags":[],"vendor":[],"product":[],"attack_vector":[],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-86068","post","type-post","status-publish","format-standard","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/86068","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=86068"}],"version-history":[{"count":0,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/86068\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/media?parent=86068"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/categories?post=86068"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/tags?post=86068"},{"taxonomy":"vendor","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/vendor?post=86068"},{"taxonomy":"product","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/product?post=86068"},{"taxonomy":"attack_vector","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/attack_vector?post=86068"},{"taxonomy":"asset_type","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/asset_type?post=86068"},{"taxonomy":"severity","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/severity?post=86068"},{"taxonomy":"exploit_status","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/exploit_status?post=86068"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}