--- title: Critical MongoDB Vulnerability in zlib Protocol Headers... description: A critical vulnerability dubbed 'MongoBleed' (CVE-2025-14847) affects MongoDB versions 3.6 through 8.2.3, allowing unauthenticated attackers to read sensitive... canonical: https://daily.dev/posts/critical-mongodb-vulnerability-in-zlib-protocol-headers-exposes-memory-leakage-risk-arbkbwhog twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Critical MongoDB Vulnerability in zlib Protocol Headers Exposes Memory Leakage Risk | daily.dev og:description: A critical vulnerability dubbed 'MongoBleed' (CVE-2025-14847) affects MongoDB versions 3.6 through 8.2.3, allowing unauthenticated attackers to read sensitive... og:url: https://daily.dev/posts/critical-mongodb-vulnerability-in-zlib-protocol-headers-exposes-memory-leakage-risk-arbkbwhog og:image: https://api.daily.dev/og/posts/aRBKBwhOg.png og:image:alt: Critical MongoDB Vulnerability in zlib Protocol Headers Exposes Memory Leakage Risk og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Critical MongoDB Vulnerability in zlib Protocol Headers Exposes Memory Leakage Risk **[Collections](https://daily.dev/sources/collections)** · 2 min read · 1 upvotes · 0 comments ## Summary A critical vulnerability dubbed 'MongoBleed' (CVE-2025-14847) affects MongoDB versions 3.6 through 8.2.3, allowing unauthenticated attackers to read sensitive data from server memory through a zlib compression flaw. With over 87,000 instances vulnerable worldwide and active exploitation underway, MongoDB has released patches for versions 8.2.3, 8.0.17, 7.0.28, 6.0.27, 5.0.32, and 4.4.30. Organizations should upgrade immediately or disable zlib compression as a temporary mitigation, as publicly available exploit code has accelerated attacks targeting major organizations. ## Content In December 2025, a high-severity vulnerability known as "MongoBleed" (CVE-2025-14847) was disclosed, affecting MongoDB versions 3.6 through 8.2.3. This flaw, with a CVSS score of 8.7, stems from a logic error in the zlib compression protocol headers. It allows unauthenticated attackers to read uninitialized heap memory, potentially exposing sensitive information such as passwords, API keys, and session tokens. The vulnerability, which affects over 87,000 instances worldwide, is being actively exploited. "MongoBleed" manipulation enables attackers to send specially crafted network packets to extract data from server memory without authentication. This can lead to unauthorized access to user information, cryptographic materials, and other sensitive data. The exploitation is reminiscent of the 2014 Heartbleed incident, given its broad potential impact and ease of execution. MongoDB responded by releasing patches on December 19, urging users to upgrade to secure versions 8.2.3, 8.0.17, 7.0.28, 6.0.27, 5.0.32, or 4.4.30. Organizations unable to upgrade immediately are advised to disable zlib compression as a temporary mitigation measure. Additionally, restrictions on network exposure and security hardening are recommended to prevent unauthorized access. Publicly available proof-of-concept code has accelerated the exploitation of this flaw, contributing to incidents targeting major organizations, including the gaming company Ubisoft. Despite MongoDB's swift actions to patch Atlas instances, many self-hosted servers remain vulnerable, highlighting the crucial need for proactive security updates. Security agencies such as CISA have listed "MongoBleed" in their catalog of known exploited vulnerabilities, further emphasizing the urgency for organizations to address this critical issue. --- Tags: [#security](https://daily.dev/tags/security), [#devops](https://daily.dev/tags/devops), [#database](https://daily.dev/tags/database), [#vulnerability](https://daily.dev/tags/vulnerability), [#mongodb](https://daily.dev/tags/mongodb) [View this post on daily.dev](https://daily.dev/posts/critical-mongodb-vulnerability-in-zlib-protocol-headers-exposes-memory-leakage-risk-arbkbwhog) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Critical MongoDB Vulnerability in zlib Protocol Headers Exposes Memory Leakage Risk","url":"https://daily.dev/posts/critical-mongodb-vulnerability-in-zlib-protocol-headers-exposes-memory-leakage-risk-arbkbwhog","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/critical-mongodb-vulnerability-in-zlib-protocol-headers-exposes-memory-leakage-risk-arbkbwhog"},"datePublished":"2025-12-26T20:24:49.736Z","dateModified":"2025-12-30T19:32:40.844Z","description":"A critical vulnerability dubbed 'MongoBleed' (CVE-2025-14847) affects MongoDB versions 3.6 through 8.2.3, allowing unauthenticated attackers to read sensitive...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/b1ba3795847b72c288d1e5f3dce45805?_a=AQAEulh","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/b1ba3795847b72c288d1e5f3dce45805?_a=AQAEulh","isAccessibleForFree":true,"articleSection":"Collections","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Collections","logo":"https://media.daily.dev/image/upload/s--fk_6ycEi--/f_auto,q_auto/v1780996001/logos/collections?_a=BAMAMiWQ0","url":"https://daily.dev/sources/collections"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/critical-mongodb-vulnerability-in-zlib-protocol-headers-exposes-memory-leakage-risk-arbkbwhog","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":1},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"security,devops,database,vulnerability,mongodb","timeRequired":"PT2M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Collections","item":"https://daily.dev/sources/collections"},{"@type":"ListItem","position":3,"name":"Critical MongoDB Vulnerability in zlib Protocol Headers Exposes Memory Leakage Risk"}]} ```