# CVE-2021-41126: Deleted Admin Can Sign In to Admin Interface

> Deleted administrator accounts can still sign in to the backend, allowing unauthorized access to administrative functions.

- **Severity:** High 7.2 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 Oct 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-6gjf-7w99-j7x7

## What is CVE-2021-41126?

CVE-2021-41126 is a high-severity authentication bypass vulnerability in Octobercms October, published on 6 Oct 2021. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

October is a Content Management System (CMS) and web platform built on the the Laravel PHP Framework. In affected versions administrator accounts which had previously been deleted may still be able to sign in to the backend using October CMS v2.0. The issue has been patched in v2.1.12 of the october/october package. There are no workarounds for this issue and all users should update.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2021-41126?

4 open source packages ship an affected version, including october/october and october/system. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `october/october` | Packagist | From 2.1.0 | 2.1.12 |
| `october/october` | Packagist | From 2.1.0 | 2.1.12 |
| `october/system` | Packagist | From 2.1.0 | 2.1.12 |
| `october/system` | Packagist | From 2.1.0 | 2.1.12 |

Products: Octobercms October.

## How do I fix CVE-2021-41126?

Upgrade october/october to 2.1.12 or later.

## Is CVE-2021-41126 being exploited?

There is no known exploitation of CVE-2021-41126 in the wild and no public exploit code.

## Other vulnerabilities in Octobercms October

- [CVE-2021-32648](https://insights.sbomify.com/CVE-2021-32648/): October CMS Improper Authentication (high 8.2, exploited in the wild)
- [CVE-2021-3311](https://insights.sbomify.com/CVE-2021-3311/): October CMS Session ID not invalidated after logout (critical 9.8)
- [CVE-2017-1000194](https://insights.sbomify.com/CVE-2017-1000194/): October CMS File Upload Vulnerability (critical 9.8)
- [CVE-2017-1000196](https://insights.sbomify.com/CVE-2017-1000196/): Code injection in n/a (critical 9.8)
- [CVE-2017-1000197](https://insights.sbomify.com/CVE-2017-1000197/): Path traversal in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-41126 and fix it if it is affected.

What it is: CVE-2021-41126 is a high-severity authentication bypass vulnerability in Octobercms October, published on 6 Oct 2021. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-41126 in the wild and no public exploit code.

Affected packages and fixed versions:
- october/october (Packagist): affected from 2.1.0; fixed in 2.1.12
- october/october (Packagist): affected from 2.1.0; fixed in 2.1.12
- october/system (Packagist): affected from 2.1.0; fixed in 2.1.12
- october/system (Packagist): affected from 2.1.0; fixed in 2.1.12

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-41126/ (Markdown: https://insights.sbomify.com/CVE-2021-41126/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-41126
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-41126
- OSV: https://osv.dev/vulnerability/CVE-2021-41126

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-41126/
Summaries are generated and may contain mistakes; the official description above is the record.