---
cve: "CVE-2026-103858"
severity: "MEDIUM"
cvss: 5.3
epss: ""
vendor: "MISP"
kev: false
exploited: false
published: "2026-10-01 12:17:16"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-10-05T17:29:45+02:00"
---

# CVE-2026-103858

> 5.3 MEDIUM · 🧪 PoC

## Beschreibung

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:

## CNA-Record (Kanon, cvelistV5)

- CNA: **CIRCL**
- State: PUBLISHED
- Stand: 2026-10-01 15:00:57
- CNA-CVSS: **5.3** (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N`)

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **none**
  - Automatable: **no**
  - Technical Impact: **partial**

## CVSS-Vektor

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

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Gering | warn |
| UI Interaktion | Keine | bad |

## Patch verfügbar (OSV)

- 79fbd4c75 (Commit)

## BSI-Hinweise (deutsch)

- [MISP: Mehrere Schwachstellen](https://wid.cert-bund.de/portal/wid/sicherheitshinweis/WID-SEC-W-2026-3705) — _BSI-Einstufung: hoch_
  Ein Angreifer kann mehrere Schwachstellen in MISP ausnutzen, um erweiterte Berechtigungen zu erlangen, beliebigen Code auszuführen, Daten offenzulegen und zu manipulieren oder Cross-Site-Scripting-Angriffe durchzuführen.

## Referenzen

- <https://github.com/MISP/MISP/commit/79fbd4c75>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-103858) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_