CVE-2026-77274Public exploitNetwork attack vectorHinoki check available

SSRF via backslash authority confusion

Published Sep 22, 2026 · Updated Sep 22, 2026

SSRF in MCP Atlassian before 0.22.0 allows remote attackers to reach internal services through crafted Atlassian URL headers. The validate_url_for_ssrf function validates the urllib.parse hostname, while Requests interprets a backslash-delimited authority as a different destination. The MCP HTTP endpoint must accept the header-based Jira or Confluence URL flow; successful requests reach loopback or internal services.

CVSS severityUnavailable
Unscored
EPSS probability0.32%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

SSRF in MCP Atlassian before 0.22.0 allows remote attackers to reach internal services through crafted Atlassian URL headers. The validate_url_for_ssrf function validates the urllib.parse hostname, while Requests interprets a backslash-delimited authority as a different destination. The MCP HTTP endpoint must accept the header-based Jira or Confluence URL flow; successful requests reach loopback or internal services.

The record

CVE
CVE-2026-77274
Published
Sep 22, 2026
Updated
Sep 22, 2026
Vendor
sooperset
Product
MCP Atlassian
Classifications
CWE-918, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 22, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.22.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

sooperset · MCP Atlassianversion=< 0.22.0

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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