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CVE-2021-22958

CRITICAL
9.8
CVSS Score
Published: October 7, 2021 at 01:35 PM UTC
Updated: June 17, 2026 at 03:38 AM UTC
1 product affected across 1 vendorConcrete CMS

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Severity
CRITICAL9.8
Exploit prediction
EPSS 1%

Description

A Server-Side Request Forgery vulnerability was found in concrete5 < 8.5.5 that allowed a decimal notation encoded IP address to bypass the limitations in place for localhost allowing interaction with local services. Impact can vary depending on services exposed.CVSSv2.0 AV:A/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:N

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Concrete CMS· Concretecms
95%
v < 8.5.5
Vendor states this is fixed in 8.5.5 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (2)

x_refsource_MISCRelease NotesVendor Advisory
Source: [email protected]
https://documentation.concretecms.org/developers/introduction/version-history/855-release-notes
x_refsource_MISCIssue TrackingPermissions RequiredThird Party Advisory
Source: [email protected]
https://hackerone.com/reports/863221

CVSS

9.8CRITICAL[email protected]
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-918

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