{"id":56075,"date":"2025-06-30T09:39:17","date_gmt":"2025-06-30T09:39:17","guid":{"rendered":""},"modified":"2025-09-26T20:58:48","modified_gmt":"2025-09-27T02:58:48","slug":"cve-2025-52566-heap-overflow-vulnerability-in-llama-cpp-s-tokenizer-implementation","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-52566-heap-overflow-vulnerability-in-llama-cpp-s-tokenizer-implementation\/","title":{"rendered":"<strong>CVE-2025-52566: Heap Overflow Vulnerability in llama.cpp&#8217;s Tokenizer Implementation<\/strong>"},"content":{"rendered":"<p><strong>Overview<\/strong><\/p>\n<p>The Common Vulnerabilities and Exposures (CVE) system has recently reported a severe vulnerability, CVE-2025-52566. This vulnerability is found in the llama.cpp inference engine used in several Low-Level Abstract Machine (LLM) models coded in C\/C++. It poses a significant risk to systems utilizing these models, <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-49415-path-traversal-vulnerability-in-fw-gallery-with-potential-for-system-compromise\/\"  data-wpil-monitor-id=\"62411\">potentially leading to full system<\/a> compromise or data leakage.<br \/>\nThe <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-6191-high-severity-integer-overflow-vulnerability-in-google-chrome-s-v8-engine\/\"  data-wpil-monitor-id=\"62991\">vulnerability is particularly concerning due to its high severity<\/a> score (CVSS 8.6) and the potential widespread impact it could have. This is <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-27216-privilege-escalation-in-uisp-application-due-to-incorrect-permission-assignment\/\"  data-wpil-monitor-id=\"84393\">due to the widely employed LLM models in various applications<\/a> across various industries. Any exploit could result in severe consequences, making it <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2023-47294-critical-vulnerability-in-ncr-terminal-handler-v1-5-1-allows-user-account-manipulation\/\"  data-wpil-monitor-id=\"63760\">critical for users<\/a> to understand and mitigate this risk promptly.<\/p>\n<p><strong>Vulnerability Summary<\/strong><\/p>\n<p>CVE ID: CVE-2025-52566<br \/>\nSeverity: High (CVSS score 8.6)<br \/>\nAttack Vector: Local Network<br \/>\nPrivileges Required: Low<br \/>\nUser Interaction: None<br \/>\nImpact: <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-6370-critical-vulnerability-in-d-link-dir-619l-2-06b01-leading-to-potential-system-compromise\/\"  data-wpil-monitor-id=\"63455\">Potential system<\/a> compromise or data leakage<\/p>\n<p><strong>Affected Products<\/strong><\/p><div id=\"ameeb-3943184425\" 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>LLM models | <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=\"77961\">Prior to version<\/a> b5721<\/p>\n<p><strong>How the Exploit Works<\/strong><\/p>\n<p>The CVE-2025-52566 vulnerability is a heap <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-6163-critical-buffer-overflow-vulnerability-in-totolink-a3002ru\/\"  data-wpil-monitor-id=\"62375\">overflow<\/a> vulnerability in the llama.cpp&#8217;s tokenizer implementation. This <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-6148-buffer-overflow-vulnerability-in-totolink-a3002ru\/\"  data-wpil-monitor-id=\"62377\">vulnerability stems from a signed vs. unsigned integer overflow<\/a> in the token copying size comparison process. An attacker can exploit this <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-24919-deserialization-of-untrusted-input-vulnerability-in-dell-controlvault3\/\"  data-wpil-monitor-id=\"63454\">vulnerability by providing a specially crafted text input<\/a> during the tokenization process.<br \/>\nThis situation results in the <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-49847-buffer-overflow-vulnerability-in-llama-cpp-leading-to-potential-code-execution\/\"  data-wpil-monitor-id=\"62600\">llama.cpp inference engine overflowing<\/a>, which in turn leads to unintended and potentially harmful behavior. The heap overflow allows for the <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-49220-pre-authentication-remote-code-execution-in-trend-micro-apex-central\/\"  data-wpil-monitor-id=\"62559\">execution of arbitrary code<\/a>, which can compromise the system or lead to data leakage.<\/p>\n<p><strong>Conceptual Example Code<\/strong><\/p><div id=\"ameeb-751585253\" 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>To illustrate, consider the following conceptual example of how the vulnerability might be exploited. This example assumes the attacker has access to the local network and can provide malicious input to the <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-49151-unauthenticated-attackers-can-forge-json-web-tokens-in-microsens-nmp-web\/\"  data-wpil-monitor-id=\"64545\">tokenization<\/a> process.<\/p>\n<pre><code class=\"\" data-line=\"\">#include &quot;llama_vocab.h&quot;\nint main() {\nllama_vocab vocab;\nstd::string malicious_input = &quot;specially crafted text causing overflow...&quot;;\n\/\/ Trigger the overflow vulnerability\nvocab.tokenize(malicious_input);\nreturn 0;\n}<\/code><\/pre>\n<p>In this example, the `malicious_input` string is <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-33077-local-stack-based-buffer-overflow-vulnerability-in-ibm-engineering-systems-design-rhapsody\/\"  data-wpil-monitor-id=\"68370\">designed to cause an integer overflow<\/a> in the tokenization process, leading to a heap overflow. This could potentially allow the attacker to <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-49212-trend-micro-endpoint-encryption-policyserver-pre-authentication-remote-code-execution-vulnerability\/\"  data-wpil-monitor-id=\"62586\">execute arbitrary code<\/a> or cause detrimental system behaviors.<\/p>\n<p><strong>Recommendations for Mitigation<\/strong><\/p>\n<p>To <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-39486-rankie-sql-injection-vulnerability-and-mitigation-measures\/\"  data-wpil-monitor-id=\"62560\">mitigate this vulnerability<\/a>, users should apply the patch provided by the vendor, which is available in version b5721 and later of the LLM models. Additionally, the <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-31100-unrestricted-file-upload-leads-to-web-shell-deployment-in-mojoomla-school-management\/\"  data-wpil-monitor-id=\"84738\">deployment of a Web<\/a> Application Firewall (WAF) or an Intrusion Detection System (IDS) can provide temporary mitigation until the patch can be applied. Furthermore, it&#8217;s advised to adhere to best practices such as limiting <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-29970-microsoft-brokering-file-system-privilege-escalation-vulnerability\/\"  data-wpil-monitor-id=\"65065\">system privileges<\/a> and monitoring system behavior for unusual activities.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Overview The Common Vulnerabilities and Exposures (CVE) system has recently reported a severe vulnerability, CVE-2025-52566. This vulnerability is found in the llama.cpp inference engine used in several Low-Level Abstract Machine (LLM) models coded in C\/C++. It poses a significant risk to systems utilizing these models, potentially leading to full system compromise or data leakage. The [&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],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-56075","post","type-post","status-publish","format-standard","hentry","category-uncategorized","attack_vector-buffer-overflow"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/56075","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=56075"}],"version-history":[{"count":15,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/56075\/revisions"}],"predecessor-version":[{"id":77523,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/56075\/revisions\/77523"}],"wp:attachment":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/media?parent=56075"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/categories?post=56075"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/tags?post=56075"},{"taxonomy":"vendor","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/vendor?post=56075"},{"taxonomy":"product","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/product?post=56075"},{"taxonomy":"attack_vector","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/attack_vector?post=56075"},{"taxonomy":"asset_type","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/asset_type?post=56075"},{"taxonomy":"severity","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/severity?post=56075"},{"taxonomy":"exploit_status","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/exploit_status?post=56075"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}