How severe is CVE-2026-27825?

CVE-2026-27825 has a CVSS 3.x base score of 9.0, rated critical severity. It is exploitable over an adjacent network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-27825 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-27825?

CVE-2026-27825 affects Mcp-atlassian Mcp Atlassian. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-27825?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-27825 have an EU (EUVD) identifier?

Yes. CVE-2026-27825 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-10810.

When was CVE-2026-27825 published?

CVE-2026-27825 was published on 2026-03-10 and last updated on 2026-06-17.

CVE-2026-27825

CVE-2026-27825 is a critical-severity vulnerability in Mcp-atlassian Mcp Atlassian with a CVSS 3.x base score of 9.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-22.

Key facts

Severity: Critical (CVSS 3.x base score 9.0)
EPSS exploit prediction: 2% (81st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-10810
Weakness: CWE-22
Affected product: Mcp-atlassian Mcp Atlassian
Published: 2026-03-10
Last modified: 2026-06-17

Description

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to version 0.17.0, the `confluence_download_attachment` MCP tool accepts a `download_path` parameter that is written to without any directory boundary enforcement. An attacker who can call this tool and supply or access a Confluence attachment with malicious content can write arbitrary content to any path the server process has write access to. Because the attacker controls both the write destination and the written content (via an uploaded Confluence attachment), this constitutes for arbitrary code execution (for example, writing a valid cron entry to `/etc/cron.d/` achieves code execution within one scheduler cycle with no server restart required). Version 0.17.0 fixes the issue.

Frequently asked questions

What is CVE-2026-27825?: MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to version 0.17.0, the `confluence_download_attachment` MCP tool accepts a `download_path` parameter that is written to without any directory boundary enforcement. An attacker who can call this tool and supply or access a Confluence attachment with malicious content can write arbitrary content to any path the server process has write access to. Because the attacker controls both the write destination and the written content (via an uploaded Confluence attachment), this constitutes for arbitrary code execution (for example, writing a valid cron entry to `/etc/cron.d/` achieves code execution within one scheduler cycle with no server restart required). Version 0.17.0 fixes the issue.
How severe is CVE-2026-27825?: CVE-2026-27825 has a CVSS 3.x base score of 9.0, rated critical severity. It is exploitable over an adjacent network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-27825 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-27825?: CVE-2026-27825 affects Mcp-atlassian Mcp Atlassian. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-27825?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-27825 have an EU (EUVD) identifier?: Yes. CVE-2026-27825 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-10810.
When was CVE-2026-27825 published?: CVE-2026-27825 was published on 2026-03-10 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:mcp-atlassian:mcp_atlassian:*:*:*:*:*:*:*:*

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