CVE-2021-41403Public exploitNetwork attack vector

Server-side request forgery via unvalidated start_index

Published Jun 15, 2022 · Updated Aug 4, 2024

Server-side request forgery in flatCore-CMS 2.0.8 allows remote attackers to make intranet requests through the page index. The acp/core/pages.index.php handler passes the start_index parameter through fc_crawler to fc_loadSourceCode without restricting the destination or URL scheme. No authentication or user interaction is reflected in NVD's assessment; the demonstrated effect is server-originated access to intranet services.

CVSS severity9.8
Critical
EPSS probability19.10%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Server-side request forgery in flatCore-CMS 2.0.8 allows remote attackers to make intranet requests through the page index. The acp/core/pages.index.php handler passes the start_index parameter through fc_crawler to fc_loadSourceCode without restricting the destination or URL scheme. No authentication or user interaction is reflected in NVD's assessment; the demonstrated effect is server-originated access to intranet services.

The record

CVE
CVE-2021-41403
Published
Jun 15, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-918, CAPEC-664, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 15, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
CAPEC-664Server Side Request Forgery
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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Your stack

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