---
cve: "CVE-2026-77255"
severity: "HIGH"
cvss: 8.6
epss: "32.9%"
vendor: "sooperset"
kev: false
exploited: false
published: "2026-09-22 19:16:49"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-23T10:20:04+02:00"
---

# CVE-2026-77255

> 8.6 HIGH · 🧪 PoC

## Beschreibung

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the Jira update_issue attachments argument is converted into local paths and routed to the attachment upload implementation without workspace validation. A caller can make the MCP server read arbitrary local files and attach them to a Jira issue, using the server as a confused deputy to exfiltrate the contents. The advisory traces the vulnerable input and processing flow through jira update_issue, attachments, upload_attachment, and file_path, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Verändert | bad |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Keine | good |
| A Verfügbarkeit | Keine | good |

## Patch verfügbar (OSV)

- b041733473f95119dd539542a43c280737a8e460 (Commit)

## Referenzen

- <https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-2xj6-xx86-cwwc>
- <https://github.com/sooperset/mcp-atlassian/pull/1448>
- <https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460>
- <https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-77255) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_