CVE-2026-77267

8.3 HIGH 0.3% 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, the X-Atlassian-Jira-Url and X-Atlassian-Confluence-Url headers are processed by _process_authentication_headers and used to construct Atlassian fetchers without calling validate_url_for_ssrf. A caller who can set these headers can supply an internal or metadata-service URL and cause the server to send requests to that destination, bypassing the incomplete CVE-2026-27826 remediation. 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: 0.3% 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 19:14 UTC ReservedThe CVE id was reserved by its CNA
2026-09-22 18:17 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: 0.3% in the next 30 days (EPSS).
Severity: 8.3 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-09-22 18:17 UTC
Last modified: 2026-09-29 18:59 UTC
Exploit probability: 0.3% · EPSS, next 30 days
Weakness: CWE-918 · Server-side request forgery
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-2026-77267.md and follow it. Check whether this project is affected by CVE-2026-77267. 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