{"id":86071,"date":"2025-12-18T16:31:00","date_gmt":"2025-12-18T16:31:00","guid":{"rendered":""},"modified":"-0001-11-30T00:00:00","modified_gmt":"-0001-11-30T06:00:00","slug":"cve-2023-49553-cesanta-mjs-2-20-0-denial-of-service-vulnerability","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2023-49553-cesanta-mjs-2-20-0-denial-of-service-vulnerability\/","title":{"rendered":"<strong>CVE-2023-49553: Cesanta mjs 2.20.0 Denial of Service Vulnerability<\/strong>"},"content":{"rendered":"<p><strong>Overview<\/strong><\/p>\n<p>The vulnerability CVE-2023-49553 is a critical concern in the cybersecurity realm. It is a vulnerability in Cesanta mjs 2.20.0 which allows a remote attacker to cause a denial of service via the mjs_destroy function. This issue affects any system using Cesanta mjs 2.20.0 and can potentially lead to system compromise or data leakage.<\/p>\n<p><strong>Vulnerability Summary<\/strong><\/p>\n<p>CVE ID: CVE-2023-49553<br \/>\nSeverity: High (7.5 CVSS Score)<br \/>\nAttack Vector: Network<br \/>\nPrivileges Required: None<br \/>\nUser Interaction: None<br \/>\nImpact: Denial of Service, potential system compromise, and data leakage.<\/p>\n<p><strong>Affected Products<\/strong><\/p><div id=\"ameeb-2883520310\" 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 originates from a flaw in the mjs_destroy function within the mjs.c file in Cesanta mjs 2.20.0. The issue allows a remote attacker to trigger a denial of service. The attacker sends a specially crafted request to the Cesanta mjs, which fails to handle it properly, thereby leading to a denial of service.<\/p>\n<p><strong>Conceptual Example Code<\/strong><\/p><div id=\"ameeb-3833281675\" 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 the vulnerability might be exploited. Note that the exact payload will depend on the specific configuration and environment.<\/p>\n<pre><code class=\"\" data-line=\"\">POST \/mjs_destroy HTTP\/1.1\nHost: target.example.com\nContent-Type: application\/json\n{ &quot;malicious_payload&quot;: &quot;specially_crafted_request_to_trigger_dos&quot; }<\/code><\/pre>\n<p><strong>Mitigation Guidance<\/strong><\/p>\n<p>The recommended mitigation strategy is to apply the vendor patch as soon as it becomes available. Meanwhile, as a temporary mitigation measure, a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can be used to block or alert on the malicious requests that attempt to exploit this vulnerability. Regularly updating and patching software is an effective practice to reduce the risk of such vulnerabilities.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Overview The vulnerability CVE-2023-49553 is a critical concern in the cybersecurity realm. It is a vulnerability in Cesanta mjs 2.20.0 which allows a remote attacker to cause a denial of service via the mjs_destroy function. This issue affects any system using Cesanta mjs 2.20.0 and can potentially lead to system compromise or data leakage. Vulnerability [&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-86071","post","type-post","status-publish","format-standard","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/86071","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=86071"}],"version-history":[{"count":0,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/86071\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/media?parent=86071"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/categories?post=86071"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/tags?post=86071"},{"taxonomy":"vendor","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/vendor?post=86071"},{"taxonomy":"product","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/product?post=86071"},{"taxonomy":"attack_vector","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/attack_vector?post=86071"},{"taxonomy":"asset_type","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/asset_type?post=86071"},{"taxonomy":"severity","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/severity?post=86071"},{"taxonomy":"exploit_status","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/exploit_status?post=86071"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}