CVE-2021-22969Network attack vector

Cloud credential disclosure via DNS-rebinding SSRF

Published Nov 19, 2021 · Updated Aug 3, 2024

SSRF in Concrete CMS before 8.5.7 allows remote authenticated users to read cloud metadata credentials through a crafted remote-file URL. The remote file downloader validates a hostname's first DNS resolution but resolves it again for the fetch, allowing DNS rebinding to redirect the request to a local address. Low-privileged access to remote file import and a cloud instance exposing metadata credentials are required; the reported impact is credential disclosure.

CVSS severity3.5
Low
EPSS probability0.86%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in Concrete CMS before 8.5.7 allows remote authenticated users to read cloud metadata credentials through a crafted remote-file URL. The remote file downloader validates a hostname's first DNS resolution but resolves it again for the fetch, allowing DNS rebinding to redirect the request to a local address. Low-privileged access to remote file import and a cloud instance exposing metadata credentials are required; the reported impact is credential disclosure.

The record

CVE
CVE-2021-22969
Published
Nov 19, 2021
Updated
Aug 3, 2024
Vendor
Concrete CMS
Product
Concrete CMS
Classifications
CWE-918, T1552.005, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 19, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=Affected version Concrete CMS (concrete5) 8.5.6 and below. Fixed in Concrete CMS version 8.5.7 and 9.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Concrete CMS · Concrete CMSversion=Affected version Concrete CMS (concrete5) 8.5.6 and below. Fixed in Concrete CMS version 8.5.7 and 9.0.0

Published CVSS scores

5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
3.5Concrete CMS Security TeamCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N
5.0NIST NVDAV:N/AC:L/Au:N/C:P/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
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

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Your stack

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