CVE-2026-77258· NVD / CVE Program· CNA GitHub_M

MCP Atlassian: Arbitrary file read/exfiltration via upload_attachment missing validate_safe_path()

Noroxi assessment

Priority: Monitor (action score 30/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.34% (FIRST EPSS).
Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
Fixed version: sooperset mcp-atlassian 0.22.0.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to sooperset mcp-atlassian 0.22.0 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, upload_attachment in src/mcp_atlassian/confluence/attachments.py accepts a caller-controlled file_path and opens the selected server-local file without restricting it to the workspace. A permitted Confluence MCP caller can upload the file as an attachment and disclose data readable by the server process. This issue is fixed in version 0.22.0.

HighCVSS 7.7 · v3.1—No exploit Fix available

Path traversal

Published: Sep 22, 2026
Updated: Sep 29, 2026
EPSS: 0.3% · 26th percentile
CWE: CWE-22

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 30 / 40 · 7.7 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.3%

CISA SSVC decision

Exploitation: proof of concept
Automatable: no
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · GitHub_M: 7.7; NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Running WordPress? Scan your site free with WP Lens

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
mcp-atlassian	mcp atlassian	cpe:2.3:a:mcp-atlassian:mcp_atlassian

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

mcp-atlassian mcp atlassianbefore 0.22.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

sooperset mcp-atlassian
- < 0.22.0affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
PyPI	mcp-atlassian	before 0.22.0	0.22.0

Same product

mcp-atlassian: all records

Other highest-scoring records for the same primary product.

CVE-2026-77244[mcp-atlassian] Authentication bypass in HTTP transport: AtlassianOpaqueTokenVerifier accepts any non-empty token
40Plan
CVE-2026-77254MCP Atlassian: Unauthenticated HTTP MCP requests can use globally configured Jira and Confluence credentials
36Monitor
CVE-2026-77243MCP Atlassian: ENABLED_TOOLS / Toolset authorization bypass
35Monitor

Published before and after this one in the same product

← EarlierCVE-2026-77250Sep 22, 2026 · MCP Atlassian: OAuth fallback token storage writes plaintext access and refresh tokens with group-readable permissions
24Monitor
← EarlierCVE-2026-77251Sep 22, 2026 · MCP Atlassian: JIRA_PROJECTS_FILTER / CONFLUENCE_SPACES_FILTER allow forbidden-project content exfiltration (one LIVE-proven on Atlassian Cloud)
33Monitor
Later →CVE-2026-77260Sep 22, 2026 · MCP Atlassian: Arbitrary local file READ via unconstrained file_path in upload_attachment (Confluence + Jira)
33Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
sooperset mcp-atlassian	0.22.0 · description	Vendor (CNA)
PyPI:mcp-atlassian	0.22.0	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

CVE-2026-772460 days apartMCP Atlassian: MCP HTTP Client Server-Local File Exfiltration via Unvalidated Attachment Upload Path
34Monitor
CVE-2026-772480 days apartMCP Atlassian: Unauthenticated arbitrary local file read via upload_attachment file_path, chained with missing auth on streamable-http transport
34Monitor
CVE-2026-772550 days apartMCP Atlassian: Arbitrary File Read & Exfiltration (Confused Deputy) in JIRA update_issue
34Monitor
CVE-2026-772620 days apartMCP Atlassian: Path Traversal / Arbitrary File Read in confluence_upload_attachment MCP tool (incomplete fix of CVE-2026-27825)
34Monitor
CVE-2026-772710 days apartMCP Atlassian: Incomplete path traversal fix allows intra-CWD module overwrite and RCE (bypass of CVE-2026-27825)
33Monitor
CVE-2026-772570 days apartMCP Atlassian: HTTP upload tools accept arbitrary server-local file paths
33Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

CVE-2026-772420 days apartMCP Atlassian: Incomplete fix for CVE-2026-27826: DNS rebinding bypasses SSRF validation (validated IP not pinned)
30Monitor

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-26-1149 · Sep 23, 2026(MCP Atlassian Güvenlik Bildirimi)

All national notices →

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: none
Availability: none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Changed
Confidentiality impact: High
Integrity impact: None
Availability impact: None

Weakness class (CWE)

CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVSS vector

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

nvd-secondary

Root cause

A user-supplied file name is joined with the allowed directory, but the result is never checked to confirm it is still inside that directory.

The bug in code

The whole CWE-22 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1const file = path.join(ROOT, req.query.name);
2res.sendFile(file);

Fixed

1const file = path.resolve(ROOT, req.query.name);
2if (!file.startsWith(ROOT + path.sep)) {
3  return res.sendStatus(400);
4}
5res.sendFile(file);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

—

Change log

Fix✗ → ✓Sep 28, 2026, 10:46 PM UTC

For records you follow, these changes also arrive as notifications. →

References

github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records