CVE-2026-85239— MISP Event Template Definition Validation Bypass Allows Persistent Denial of Service

MISP Event Template Definition Validation Bypass Allows Persistent Denial of Service

A vulnerability in MISP's event template handling allowed an authenticated user with permission to create or modify event templates to bypass validation of the template definition field. The EventTemplate::beforeValidate() method only performed semantic validation when the supplied definition was already represented as an array. If a caller instead supplied a pre-encoded string, including malformed JSON or JSON representing an unexpected data type, the value bypassed validateDefinition() and only needed to satisfy the generic notBlank validation rule. As a result, an invalid event template definition could be stored persistently in the database. When event templates were subsequently retrieved, EventTemplate::afterFind() attempted to decode the stored definition using JsonTool::decode() without handling decoding failures. A definition containing invalid JSON could therefore trigger an exception during retrieval. Because the event template index is available to all authenticated users, a single malicious or malformed template could make the event template listing and other functionality relying on EventTemplate queries return HTTP 500 errors until the offending database row was manually repaired. Valid JSON representing an unexpected type, rather than the expected JSON object, could similarly result in invalid data reaching downstream consumers. The vulnerability can therefore be exploited by a user capable of saving event templates to persist malformed template data and cause a persistent denial of service against event-template functionality for other users. The patch enforces that event template definitions must be supplied as structured objects before saving and always applies semantic validation. On retrieval, malformed JSON and definitions that do not decode to the expected structure are caught, logged, and replaced with an empty definition, preventing a malformed database entry from breaking all event template queries.  Poisoning doesn't seem reachable according to the lead developer.

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

输入验证不恰当

MISP 输入验证错误漏洞

MISP是MISP组织开源的一套开源的软件解决方案。该产品用于收集、存储、分发、共享网络安全指标,并具有威胁网络安全事件分析和恶意软件分析等功能。 MISP 2.5.45及之前版本存在输入验证错误漏洞，该漏洞源于事件模板定义字段验证不严，预编码字符串可绕过语义验证，导致无效JSON被存储并在检索时解码失败触发异常，可能导致持久拒绝服务。

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