CVE-2021-26072Network attack vector

Internal resource disclosure via blind SSRF

Published Apr 1, 2021 · Updated Sep 17, 2024

Blind SSRF in Atlassian Confluence Server and Data Center before 5.8.6 allows remote authenticated users to access internal resources. The WidgetConnector plugin forwards supplied resource URLs as server-side requests without reliably restricting internal destinations. Low-privileged access is required; exposed cloud metadata can disclose credentials, while the default-enabled URL allowlist limits reachability.

CVSS severity4.3
Medium
EPSS probability38.84%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Blind SSRF in Atlassian Confluence Server and Data Center before 5.8.6 allows remote authenticated users to access internal resources. The WidgetConnector plugin forwards supplied resource URLs as server-side requests without reliably restricting internal destinations. Low-privileged access is required; exposed cloud metadata can disclose credentials, while the default-enabled URL allowlist limits reachability.

The record

CVE
CVE-2021-26072
Published
Apr 1, 2021
Updated
Sep 17, 2024
Vendor
Atlassian
Product
Confluence Data Center
Classifications
CWE-918, T1552.005
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 1, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record 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=unspecified <5.8.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Atlassian · Confluence Data Centerversion=unspecified <5.8.6
Atlassian · Confluence Serverversion=unspecified <5.8.6

Published CVSS scores

4.3AtlassianCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

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.

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

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
T1552.005Cloud Instance Metadata API

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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