October CMS auth bypass and account takeover
Impact
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.
Patches
- Issue has been patched in Build 472 and v1.1.5
- Shortened patch instructions
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 hello@octobercms.com
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Composer package | october/system | < 1.0.472, >= 1.1.1, < 1.1.5 | 1.0.472, 1.1.5 |
References
- https://github.com/octobercms/october/security/advisories/GHSA-h76r-vgf3-j6w5
- https://nvd.nist.gov/vuln/detail/CVE-2021-29487
- https://github.com/octobercms/library/commit/016a297b1bec55d2e53bc889458ed2cb5c3e9374
- https://github.com/octobercms/library/commit/5bd1a28140b825baebe6becd4f7562299d3de3b9
- https://github.com/octobercms/october
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N- Weakness (CWE)
CWE-287- Platform
- Composer
- Package
october/system- Disclosed
- 30.08.2021
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-h76r-vgf3-j6w5 - CC BY 4.0
Vulnerability history: october/system
All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 25
- First → latest
- 06.2020 09.2026
- Without a fix
- 0
- Exploited in attacks
- 1
Severity breakdown
- Critical 1
- High 8
- Medium 9
- Low 7
Disclosures per year
- 2020: 1
- 2021: 3
- 2022: 6
- 2023: 3
- 2024: 2
- 2025: 1
- 2026: 9
-
October CMS auth bypass and account takeover this entry
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