# CVE-2026-52824: Kimai: Default APP_SECRET in Docker Image Enables Cookie Forgery and Account Takeover

> An unauthenticated attacker can forge authentication cookies to take over accounts in Kimai deployments using the default Docker image secret.

- **Severity:** Critical 9.1 (`CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Sep 2026
- **Updated:** 16 Sep 2026
- **Also known as:** GHSA-jr9p-4h4j-6c58

## What is CVE-2026-52824?

CVE-2026-52824 is a critical vulnerability in kimai, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Kimai is an open-source time tracking application. Prior to 2.58.0, the official Docker image sets APP_SECRET to the public value change_this_to_something_unique in Dockerfile, and .docker/entrypoint.sh neither replaces nor rejects that value before Symfony uses it as kernel.secret. An unauthenticated attacker who reaches a deployment that did not override APP_SECRET, knows a username, correctly guesses the account ID associated with that username, and targets an account without active two-factor authentication can forge HMAC-protected authentication artifacts, including KIMAI_REMEMBER cookies and login links, to access the account without its password. The updated entrypoint generates and persists a random secret when no safe operator-provided value exists. This issue is fixed in version 2.58.0.

Weakness: CWE-1188 (Initialization of a Resource with an Insecure Default)

## Which versions are affected by CVE-2026-52824?

2 open source packages ship an affected version, including kimai/kimai.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `kimai/kimai` | Packagist | All versions | 2.58.0 |
| `kimai/kimai` | Packagist | All versions | 2.58.0 |

## How do I fix CVE-2026-52824?

Upgrade kimai/kimai to 2.58.0 or later.

## Is CVE-2026-52824 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-52824 exists.

Public exploit code:

- Technical analysis and PoC of CVE-2026-52824: default APP_SECRET in the Kimai Docker image enabling unauthenticated login link forgery. Affects <= 2.57.0, fixed in 2.58.0. (github_poc): https://github.com/AzureADTrent/CVE-2026-52824
- Kimai <= 2.57.0 - Default APP_SECRET Authentication Bypass (nuclei): http/cves/2026/CVE-2026-52824.yaml

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-52824 and fix it if it is affected.

What it is: CVE-2026-52824 is a critical vulnerability in kimai, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-52824 exists.

Affected packages and fixed versions:
- kimai/kimai (Packagist): affected all versions; fixed in 2.58.0
- kimai/kimai (Packagist): affected all versions; fixed in 2.58.0

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-2026-52824/ (Markdown: https://insights.sbomify.com/CVE-2026-52824/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-52824
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-52824
- OSV: https://osv.dev/vulnerability/CVE-2026-52824

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-52824/
Summaries are generated and may contain mistakes; the official description above is the record.