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Not in CISA KEV
HIGH severity

CVE-2021-41126 — october

HIGH

CVE-2021-41126 is a high-severity (CVSS 7.2) Improper Authentication vulnerability in october/october. A fix is available for october/october — see the affected versions and patch details below.

Deleted Admin Can Sign In to Admin Interface

Also known asGHSA-6gjf-7w99-j7x7
Published
Updated
Affected
2 pkgs
Patched
2 / 2
Exploits
None indexed
Exploitation data as of Oct 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.1%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs64th percentile — riskier than 64% of all scored CVEsHighest risk
0.56%0.90%1.25%1.59%1.1%1.1%1.1%1.1%Jul 26Oct 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-41126 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

2 pkgs affected
🐘october/october🐘october/system

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Impact

Assuming an administrator once had previous access to the admin interface, they may still be able to sign in to the backend using October CMS v2.0.

Patches

The issue has been patched in v2.1.12

Workarounds

  • Reset the password of the deleted accounts to prevent them from signing in.

  • Please contact [email protected] for code change instructions if you are unable to upgrade.

References

Credits to: • Daniel Bidala

For more information

If you have any questions or comments about this advisory:

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
🐘Packagistoctober/october≥ 2.1.0&&< 2.1.122.1.12composer require october/october:^2.1.12
🐘Packagistoctober/system≥ 2.1.0&&< 2.1.122.1.12composer require october/system:^2.1.12

Affected Products

1 product · 1 configurations
Application
octoberoctobercms
≥ 2.0.0 && < 2.1.12
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for october/october, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update october/october to 2.1.12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-41126 is resolved across your whole dependency graph.

  3. Workarounds

    Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

### Impact Assuming an administrator once had previous access to the admin interface, they may still be able to sign in to the backend using October CMS v2.0. ### Patches The issue has been patched in v2.1.12 ### Workarounds - Reset the password of the deleted accounts to prevent them from signing in. - Please contact [email protected] for code change instructions if you are unable to upgrade. ### References Credits to: • Daniel Bidala ### For more information If you have any questions or comments about this advisory: * Email us at [[email protected]](mailto:[email protected])
O3 Security · Impact-Aware SCA

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CVE-2021-41126: october — Fixed in 2.1.12