CVE-2021-43136Public exploitNetwork attack vector

Unauthenticated account access via forgeable SSO tokens

Published Nov 10, 2021 · Updated Aug 4, 2024

Authentication bypass in FormaLMS 2.4.4 and earlier allows remote attackers to access the platform as an arbitrary user via SSO. The index.php SSO path validates an MD5 token derived from the username, expiration time, and a shipped hard-coded secret or an empty configured value. When SSO token authentication is enabled and the secret remains default or empty, knowledge of a username is enough to forge a valid session.

CVSS severity9.8
Critical
EPSS probability15.72%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in FormaLMS 2.4.4 and earlier allows remote attackers to access the platform as an arbitrary user via SSO. The index.php SSO path validates an MD5 token derived from the username, expiration time, and a shipped hard-coded secret or an empty configured value. When SSO token authentication is enabled and the secret remains default or empty, knowledge of a username is enough to forge a valid session.

The record

CVE
CVE-2021-43136
Published
Nov 10, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-798, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 10, 2021CVE 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

6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-798Use of Hard-coded Credentials
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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