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CVE-2026-103659— MISP: Object Distribution ACL Bypass via Event Flattening Exposes Organisation-Only Attributes

Quick assessment

Affected
MISP MISP
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

MISP 在事件扁平化（event flattening）功能中存在一个授权绕过漏洞。当用户请求启用 选项的事件时，应用程序会从查询中移除 Object（对象）的包含关系，并将对象的属性作为顶层事件属性返回。在此过程中，原本应用于这些属性的对象级别分发（distribution）和共享组（sharing-group）访问控制检查未被重新应用。 因此，能够查看社区分发（community-distributed）事件的用户，可以获取属于仅限组织内部访问的对象（distribution 级别为 0）或受特定共享组限制的

CVSS 7.1 · High EPSS 0.23% · P12

Possible ATT&CK Techniques 1 AI

T1528 · Steal Application Access Token

Affected Version Matrix 1

VendorProduct Version RangeStatus
MISP MISP < 2.5.48 affected
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I. Basic Information for CVE-2026-103659

Vulnerability Information
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Vulnerability Title
MISP: Object Distribution ACL Bypass via Event Flattening Exposes Organisation-Only Attributes
Source: CVE Program / CVE List V5
Vulnerability Description
MISP contains an authorization bypass in the event flattening feature. When a user requests an event with the flatten option enabled, the application removes the Object containment from the query and returns object attributes as top-level event attributes. In doing so, the object-level distribution and sharing-group access control check was not re-applied to those attributes. As a result, a user who can view a community-distributed event could retrieve attributes belonging to organisation-only objects (distribution level 0) or objects restricted to a specific sharing group, even though the user's organisation does not have access to those objects. This constitutes an unauthorized disclosure of sensitive threat intelligence data. A secondary issue was introduced by the initial remediation: the fix reused the full Object contain conditions (including soft-delete state) as the gate for flattened attributes, causing an event owner requesting deleted attributes to lose all attributes whose parent object was still live. The final fix isolates the distribution ACL condition as the sole gate. Preconditions: - An authenticated user with access to a community-distributed event - The event contains at least one object with a distribution level or sharing group that restricts access beyond the event's own distribution Impact: - Unauthorized disclosure of attributes belonging to restricted objects - Potential exposure of organisation-specific threat intelligence to other organisations Affected versions: <2.5.48
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
授权机制缺失
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
MISP MISP 0 ~ 2.5.48 cpe:2.3:a:misp:misp:*:*:*:*:*:*:*:*

II. Public POCs for CVE-2026-103659

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III. Intelligence Information for CVE-2026-103659

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Patches & Fixes for CVE-2026-103659 (2)

Same Patch Batch · MISP · 2026-10-01 · 6 CVEs total

CVE-2026-103655 9.3 CRITICAL MISP TOTP Code Replay Allows Duplicate Authentication Within Validity Period
CVE-2026-103651 7.6 HIGH MISP HOTP Token Replay via Stale Session-Cached Counter Allows Second-Factor Authenticatio
CVE-2026-103858 5.3 MEDIUM MISP Incomplete Thread Authorization Allows Unauthorized Read and Post Access to Discussio
CVE-2026-103662 5.1 MEDIUM MISP Reflected XSS in Taxonomy Tag Confirmation Forms
CVE-2026-103664 4.8 MEDIUM MISP Reflected Cross-Site Scripting via Unsanitized Analyst Data Seed Parameter

IV. Related Vulnerabilities

Same product: MISP
Same vendor: MISP
Same weakness: CWE-862

V. Comments for CVE-2026-103659

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