CVE-2026-103858
MISP contains an incomplete authorization check in the discussion posting functionality.
Overview
CVE-2026-103858 is a known-severity vulnerability. It was published on October 1, 2026.
Technical description
MISP contains an incomplete authorization check in the discussion posting functionality. When a user submits a post to a thread or replies to an existing post, the application only verified whether the target thread was restricted to a single organization (org-only distribution). It did not enforce the full thread access control list, including sharing-group membership and event-level visibility.
As a result, an authenticated user who is outside the relevant sharing group or who does not have visibility on the associated event could:
- Read the thread title and the content of the quoted post
- Submit a new post into the discussion thread
This constitutes both an information disclosure (reading restricted thread and post content) and an integrity issue (injecting content into a thread the user is not authorized to participate in).
Affected: <2.5.48
Remediation
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
References
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Frequently asked questions
What is CVE-2026-103858?
CVE-2026-103858 is a known-severity vulnerability. It was published on October 1, 2026.
How severe is CVE-2026-103858?
CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.
How do I fix or remediate CVE-2026-103858?
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-103858?
CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-103858 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.