CVE-2026-77257

8.3 HIGH 0.4% exploit odds Fix listed Disclosure Server

What it is

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, HTTP-exposed Jira and Confluence upload tools pass a caller-provided file_path to local file operations without restricting it to the workspace. A remote MCP caller with tool access can cause the server to read sensitive local files and upload them as Atlassian attachments. The advisory traces the vulnerable input and processing flow through streamable-http, upload_attachment, and file_path, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.

At a glance

Exploitability: Can be exploited over the network with a low-privilege account. High risk of data exposure.
Exploit odds: 0.4% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-08-20 19:02 UTC ReservedThe CVE id was reserved by its CNA
2026-09-22 19:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-09-29 18:59 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.4% in the next 30 days (EPSS).
Severity: 8.3 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-09-22 19:16 UTC
Last modified: 2026-09-29 18:59 UTC
Exploit probability: 0.4% · EPSS, next 30 days
Weakness: CWE-22 · Path traversal
Record status: Analyzed

Affected

mcp-atlassian Mcp Atlassian < 0.22.0

Attack profile CVSS 4.0 · 8.3

Attack vector: Network
Complexity: Low
Attack requirements: None
Privileges needed: Low
User interaction: None
Confidentiality: High
Integrity: None
Availability: None

Raw vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-77257.md and follow it. Check whether this project is affected by CVE-2026-77257. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record