GCD AI RADAR
incidents/AIR-2026-0161

CVE-2026-77255: MCP Atlassian Arbitrary File Read and Exfiltration Vulnerability

Attack on AI2 Disclosed vulnerabilityInfrastructure vulnerabilityAgent hijack

An insecure file handling vulnerability in MCP Atlassian allows callers to trick the server into reading arbitrary local files and attaching them to Jira issues. This acts as a confused deputy vector for data exfiltration.

disclosed CVENo confirmed exploitation, so this record is tracked as a disclosed vulnerability and not counted as an incident. It moves into the counts if CISA or the vendor confirms exploitation. Why

Details

type
Attack on AI
An AI model, agent or AI-powered product was the thing exploited, abused or leaked.
categories
  • Infrastructure vulnerabilityprimary
    CVEs and advisories in AI frameworks, inference servers, MCP servers, AI developer tools and hosting stacks.
  • Agent hijack
    An AI agent is tricked into unauthorized actions: tool misuse, data exfiltration through the agent, or acting against its principal.
owasp llm top 10
mitre atlas
Both rows are derived from the type and categories (OWASP 2025 edition, ATLAS release 2026.09), not classified per record. How
severity
2 · Disclosed vulnerability
CVE or vendor advisory, patched or patchable, no confirmed exploitation.
targets
Framework / tooling
products
MCP Atlassian
incident date
22 Sep 2026
first reported
22 Sep 2026
origin
NVD
Vulnerability record from NVD / the GitHub Advisory Database. This product uses the NVD API but is not endorsed or certified by the NVD.
classifier confidence
0.95 · published at or above 0.80; see the methodology
tags
CVE-2026-77255 · mcp · confused-deputy · arbitrary-file-read
record
created 2026-10-18 06:33Z · updated 2026-10-18 06:33Z · json

Sources · 1

  1. 2026-09-22
    CVE-2026-77255: MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira).
    NVD · nvd.nist.gov/vuln/detail/CVE-2026-77255

Titles and links belong to their publishers. The summary above is written by GCD AI RADAR in its own words; data is CC BY-SA 4.0.

Related incidents