October CMS auth bypass and account takeover

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.4 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS

• CVE-2021-29487: 0.90% estimated exploitation activity in the next 30 days; percentile 59.55 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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…

Published by the source

30 Aug 2021, 16:13 UTC

Last modified by the source

29 Jan 2023, 05:02 UTC

Source last checked

26 Oct 2026, 14:00 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-h76r-vgf3-j6w5

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# Patch Next advisory brief: CVE-2021-29487

Advisory: October CMS auth bypass and account takeover
IDs: CVE-2021-29487, GHSA-h76r-vgf3-j6w5
Record: https://patchnext.com/advisories/cve-2021-29487 (revision 1, source checked 26 Oct 2026, 14:00 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.4)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: october/system 1.1.5, 1.0.472. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist october/system: affected < 1.0.472; >= 1.1.1, < 1.1.5; fixed in 1.1.5, 1.0.472

## Suggested inspection (read-only)
- Packagist october/system: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on october/system.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-h76r-vgf3-j6w5 (GitHub-reviewed advisory GHSA-h76r-vgf3-j6w5 lists affected ranges: Packagist october/system >=0 =1.1.1 <1.1.5)

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