CVE-2021-29487Network attack vector

Frontend account takeover via persist-cookie type juggling

Published Aug 26, 2021 · Updated Aug 3, 2024

Improper authentication in October CMS 1.0.471 and 1.1.1 through 1.1.4 allows remote attackers to take over frontend accounts. The frontend User model's checkPersistCode method compares a supplied persist-cookie code with stored account state using PHP loose equality, permitting type coercion. Exploitation requires the Laravel encryption and signing key and a targeted frontend user to be logged in; successful requests assume that account without appearing in access logs.

CVSS severity7.4
High
EPSS probability0.90%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in October CMS 1.0.471 and 1.1.1 through 1.1.4 allows remote attackers to take over frontend accounts. The frontend User model's checkPersistCode method compares a supplied persist-cookie code with stored account state using PHP loose equality, permitting type coercion. Exploitation requires the Laravel encryption and signing key and a targeted frontend user to be logged in; successful requests assume that account without appearing in access logs.

The record

CVE
CVE-2021-29487
Published
Aug 26, 2021
Updated
Aug 3, 2024
Vendor
October CMS
Product
October CMS
Classifications
CWE-287, T1606.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 26, 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=>= 1.0.471, < 1.0.472
  2. Affected versionversion=>= 1.1.1, < 1.1.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

October CMS · October CMSversion=>= 1.0.471, < 1.0.472; version=>= 1.1.1, < 1.1.5

Published CVSS scores

7.4GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-287Improper Authentication
T1606.001Forge Web Credentials: Web Cookies

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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