CVE-2021-29487

Workarounds

Apply https://github.com/octobercms/library/commit/016a297b1bec55d2e53bc889458ed2cb5c3e9374 and https://github.com/octobercms/library/commit/5bd1a28140b825baebe6becd4f7562299d3de3b9 to your installation manually if you are unable to upgrade.

[Update 2022-01-20] Shortened patch instructions can be found here.

Recommendations

We recommend the following steps to make sure your server stays secure:

• Keep server OS and system software up to date.
• Keep October CMS software up to date.
• Use a multi-factor authentication plugin.
• Change the default backend URL or block public access to the backend area.
• Include the Roave/SecurityAdvisories Composer package to ensure that your application doesn't have installed dependencies with known security vulnerabilities.

References

Bugs found as part of Solar Security CMS Research. Credits to:
• Andrey Basarygin
• Andrey Guzei
• Mikhail Khramenkov
• Alexander Sidukov
• Maxim Teplykh

For more information

If you have any questions or comments about this advisory:

• Email us at [email protected]

An attacker can exploit this vulnerability to bypass authentication using a specially crafted persist cookie.

• To exploit this vulnerability, an attacker must obtain a Laravel’s secret key for cookie encryption and signing.
• Due to the logic of how this mechanism works, a targeted user account must be logged in while
  the attacker is exploiting the vulnerability.
• Authorization via persist cookie not shown in access logs.

The application does not adequately verify the identity of a user, device, or process before granting access. Typical impact: unauthorized access to functions or data reserved for authenticated parties.

CVE-2021-29487 has a CVSS score of 7.4 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.0.472, 1.1.5); upgrading removes the vulnerable code path.

Kodem intelligence

• Issue has been patched in Build 472 and v1.1.5
• Shortened patch instructions

1. What is CVE-2021-29487? CVE-2021-29487 is a high-severity improper authentication vulnerability in october/system (composer), affecting versions < 1.0.472. It is fixed in 1.0.472, 1.1.5. The application does not adequately verify the identity of a user, device, or process before granting access.
2. How severe is CVE-2021-29487? CVE-2021-29487 has a CVSS score of 7.4 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of october/system are affected by CVE-2021-29487? october/system (composer) versions < 1.0.472 is affected.
4. Is there a fix for CVE-2021-29487? Yes. CVE-2021-29487 is fixed in 1.0.472, 1.1.5. Upgrade to this version or later.
5. Is CVE-2021-29487 exploitable, and should I be worried? Whether CVE-2021-29487 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2021-29487 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2021-29487?
   • Upgrade october/system to 1.0.472 or later
   • Upgrade october/system to 1.1.5 or later