{"id":55083,"date":"2025-06-25T09:49:20","date_gmt":"2025-06-25T09:49:20","guid":{"rendered":""},"modified":"2025-09-03T02:35:40","modified_gmt":"2025-09-03T08:35:40","slug":"cve-2025-20260-buffer-overflow-vulnerability-in-clamav-s-pdf-scanning-process","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-20260-buffer-overflow-vulnerability-in-clamav-s-pdf-scanning-process\/","title":{"rendered":"<strong>CVE-2025-20260: Buffer Overflow Vulnerability in ClamAV&#8217;s PDF Scanning Process<\/strong>"},"content":{"rendered":"<p><strong>Overview<\/strong><\/p>\n<p>In the ever-evolving landscape of cybersecurity, vulnerabilities are often discovered that can potentially compromise system security or result in data leakage. One such vulnerability, identified as CVE-2025-20260, has been detected in the PDF scanning processes of ClamAV, a popular open-source antivirus engine. This vulnerability affects any system or device that utilizes the ClamAV engine for <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-6065-arbitrary-file-deletion-vulnerability-in-image-resizer-on-the-fly-wordpress-plugin\/\"  data-wpil-monitor-id=\"61417\">scanning PDF<\/a> files. The matter is of utmost importance as it might allow an unauthenticated, remote attacker to cause a <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-6090-critical-buffer-overflow-vulnerability-in-h3c-gr-5400ax-v100r009l50\/\"  data-wpil-monitor-id=\"61411\">buffer overflow<\/a> condition, leading to a denial of service (DoS) or potentially executing arbitrary code on the affected device.<\/p>\n<p><strong>Vulnerability Summary<\/strong><\/p>\n<p>CVE ID: CVE-2025-20260<br \/>\nSeverity: Critical (CVSS: 9.8)<br \/>\nAttack Vector: Network<br \/>\nPrivileges Required: None<br \/>\nUser Interaction: None<br \/>\nImpact: <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-6091-critical-buffer-overflow-vulnerability-in-h3c-gr-3000ax-v100r007l50\/\"  data-wpil-monitor-id=\"61413\">Buffer overflow<\/a> potentially leading to a denial of service condition or execution of arbitrary code on the affected system.<\/p>\n<p><strong>Affected Products<\/strong><\/p><div id=\"ameeb-1682591975\" 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>ClamAV | All versions up to the latest release<\/p>\n<p><strong>How the Exploit Works<\/strong><\/p>\n<p>The <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-6111-critical-buffer-overflow-vulnerability-in-tenda-fh1205-2-0-0-7-775\/\"  data-wpil-monitor-id=\"61438\">vulnerability arises due to incorrect memory buffer<\/a> allocation when ClamAV processes PDF files. An attacker can exploit this <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-36631-critical-file-overwrite-vulnerability-in-tenable-agent\/\"  data-wpil-monitor-id=\"61874\">vulnerability by crafting a malicious PDF file<\/a> and submitting it to be scanned by ClamAV on the affected device. If successful, this could trigger a <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-24922-stack-based-buffer-overflow-vulnerability-in-dell-controlvault3\/\"  data-wpil-monitor-id=\"61429\">buffer overflow<\/a> condition, likely resulting in the termination of the ClamAV scanning process and a DoS condition on the affected software. Although not yet proven, it is also possible that an attacker could leverage this <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-46060-critical-buffer-overflow-vulnerability-in-totolink-n600r\/\"  data-wpil-monitor-id=\"61434\">buffer overflow<\/a> to execute arbitrary code with the privileges of the ClamAV process.<\/p>\n<p><strong>Conceptual Example Code<\/strong><\/p><div id=\"ameeb-2762729258\" 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>Here&#8217;s a conceptual example of how this vulnerability might be exploited. This pseudocode represents a maliciously crafted PDF file:<\/p>\n<pre><code class=\"\" data-line=\"\"># Pseudocode representing a malicious PDF\nclass MaliciousPDF:\ndef __init__(self):\nself.payload = &quot;A&quot;*5000  # Overflows the buffer\nmalicious_pdf = MaliciousPDF()\nClamAV.scan(malicious_pdf)  # Triggers buffer overflow<\/code><\/pre>\n<p>In the above example, the payload is an extremely large string designed to <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-6110-critical-buffer-overflow-vulnerability-in-tenda-fh1201-1-2-0-14-408\/\"  data-wpil-monitor-id=\"61435\">overflow the buffer<\/a> when scanned by ClamAV.<\/p>\n<p><strong>Recommendations<\/strong><\/p>\n<p>The recommended mitigation for this <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-50213-special-element-injection-vulnerability-in-apache-airflow-providers-snowflake\/\"  data-wpil-monitor-id=\"64011\">vulnerability is to apply the patch provided<\/a> by the vendor as soon as it is available. As a temporary countermesure, you can use a Web Application Firewall (WAF) or Intrusion Detection System (IDS) to identify and block <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=\"77843\">potential attacks<\/a>. Users are also advised to avoid scanning unsolicited PDF files and to only scan files from trusted sources.<br \/>\nStay tuned for more <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-48799-privilege-escalation-vulnerability-in-windows-update-service\/\"  data-wpil-monitor-id=\"77842\">updates on this and other cybersecurity vulnerabilities<\/a>. Protecting your <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-5867-critical-vulnerability-in-rt-thread-5-1-0-leading-to-system-compromise-or-data-leakage\/\"  data-wpil-monitor-id=\"64012\">systems and data<\/a> is our top priority.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Overview In the ever-evolving landscape of cybersecurity, vulnerabilities are often discovered that can potentially compromise system security or result in data leakage. One such vulnerability, identified as CVE-2025-20260, has been detected in the PDF scanning processes of ClamAV, a popular open-source antivirus engine. This vulnerability affects any system or device that utilizes the ClamAV engine [&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":[86,87],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-55083","post","type-post","status-publish","format-standard","hentry","category-uncategorized","attack_vector-buffer-overflow","attack_vector-dos"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/55083","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=55083"}],"version-history":[{"count":10,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/55083\/revisions"}],"predecessor-version":[{"id":70241,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/55083\/revisions\/70241"}],"wp:attachment":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/media?parent=55083"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/categories?post=55083"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/tags?post=55083"},{"taxonomy":"vendor","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/vendor?post=55083"},{"taxonomy":"product","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/product?post=55083"},{"taxonomy":"attack_vector","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/attack_vector?post=55083"},{"taxonomy":"asset_type","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/asset_type?post=55083"},{"taxonomy":"severity","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/severity?post=55083"},{"taxonomy":"exploit_status","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/exploit_status?post=55083"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}