---
title: "CVE-2026-77246: MCP Atlassian - Authorization Bypass"
description: "MCP Atlassian < 0.22.0 contains an authorization bypass caused by accepting requests without identity and allowing attacker-controlled service headers, letting attackers upload server-local files to attachment endpoints, exploit requires READ_ONLY_MODE=false."
url: https://panop.io/threat-heartbeat/CVE-2026-77246/
---

# CVE-2026-77246 MCP Atlassian - Authorization Bypass

MCP Atlassian < 0.22.0 contains an authorization bypass caused by accepting requests without identity and allowing attacker-controlled service headers, letting attackers upload server-local files to attachment endpoints, exploit requires READ\_ONLY\_MODE=false.

CVSS base score 7.4 /10

High

CISA KEV

Not listed

Public exploit

Proof of concept available

Authentication

Not required

EPSS

0.43% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-77246)

## Details

Type

Authorization Bypass

Impact

Data Tampering, File System Write

CVSS vector

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

Published

22 September 2026

Updated

15 October 2026

Weakness

[CWE-22](https://cwe.mitre.org/data/definitions/22.html)

## Vendor fix

Update to version 0.22.0 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-77246](https://nvd.nist.gov/vuln/detail/CVE-2026-77246)
- [https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460](https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460)
- [https://github.com/sooperset/mcp-atlassian/pull/1448](https://github.com/sooperset/mcp-atlassian/pull/1448)
- [https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0](https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0)
- [https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-wv8v-v4c5-v75j](https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-wv8v-v4c5-v75j)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

Panop answers these inside your environment, for this CVE and every other finding.

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