How severe is CVE-2026-52824?

No CVSS score has been assigned to CVE-2026-52824 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-52824?

CVE-2026-52824 affects the following packages: kimai/kimai (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2026-52824?

Update kimai/kimai to 2.58.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-52824 is resolved across your whole dependency graph.

How do I detect CVE-2026-52824 in my Packagist dependencies?

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

How do I mitigate CVE-2026-52824 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-52824 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-52824 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-52824?

CVE-2026-52824 has an EPSS (Exploit Prediction Scoring System) score of 1.3%, placing it in the 71th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-52824?

CVE-2026-52824 is classified as CWE-1188 (CWE-1188). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Is there exploit tooling available for CVE-2026-52824?

A Nuclei detection template exists for CVE-2026-52824, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2026-52824 published, and has it been updated?

CVE-2026-52824 was published on September 15, 2026 and was last updated on October 21, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2026-52824 — kimai

Fix: kimai/kimai@31a8f88

CVE-2026-52824 is a CWE-1188 vulnerability in kimai/kimai. A fix is available for kimai/kimai — see the affected versions and patch details below.

Kimai: Default APP_SECRET in Docker Image Enables Cookie Forgery and Account Takeover

Also known asGHSA-jr9p-4h4j-6c58

Published

Sep 15, 2026

Updated

Oct 21, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 21, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-52824.

EPSS Exploitation Probability

via FIRST.org ↗

1.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs71th percentile — riskier than 71% of all scored CVEsHighest risk

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

Real-World Exposure

1 pkg affected

🐘kimai/kimai

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

Summary

The official Kimai Docker image ships with APP_SECRET=change_this_to_something_unique as the default environment variable. The Docker entrypoint does not override or validate this value. Any Kimai instance deployed using the Docker image without explicitly setting APP_SECRET runs with a publicly-known Symfony kernel.secret, enabling an unauthenticated attacker to forge HMAC-signed cookies and login links to take over any account including super_admin.

Details

Dockerfile:263 sets ENV APP_SECRET=change_this_to_something_unique. This value is consumed by config/packages/framework.yaml:7 as kernel.secret, which Symfony uses to HMAC-sign:

The KIMAI_REMEMBER remember-me cookie
LoginLink signatures
Password reset URLs
CSRF tokens

The .docker/entrypoint.sh does not check for or replace the default sentinel value. The bare-metal .env.dist:38 ships the same default. No startup-time guard exists anywhere in the codebase that refuses to start when APP_SECRET equals the sentinel.

User IDs are sequential integers starting from 1. The first super_admin account is almost always id=1. User IDs are visible in some URLs and API responses.

A PoC was provided, but removed for security reasons.

Impact

Any Kimai instance deployed via the official Docker image without overriding APP_SECRET can be compromised from the internet. An unauthenticated attacker who can reach the Kimai URL can forge authentication tokens and log in as any user if:

a username is known AND
the correct account ID for this username is guessed AND
the account has no active 2FA (two factor) authentication

Solution

The entrypoint.sh file is updated and now contains a script that generates a random APP_SECRET via bin2hex(random_bytes(32)) which will be stored in /opt/kimai/var/data/.appsecret
The entrypoint.sh will create the file /opt/kimai/.env.local containing the APP_SECRET, either fetched from the Docker Environment or from the newly created secret file
The documentation was updated to highlight the importance of using a random secret for APP_SECRET
The Dockerfile removed default APP_SECRET=change_this_to_something_unique
Login links now contain more entropy (see GHSA-m492-gv72-xvxj) - so even without all previous changes, attackers won't be able to generate Login links even for installations that have a hard-coded APP_SECRET=change_this_to_something_unique

See https://www.kimai.org/en/security/ghsa-jr9p-4h4j-6c58 for more information.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`kimai/kimai`	all versions	2.58.0`composer require kimai/kimai:^2.58.0`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for kimai/kimai, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update kimai/kimai to 2.58.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-52824 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How to detect CVE-2026-52824

A community-maintained Nuclei template exists for this CVE. You can scan for it directly:

nuclei -id cve-2026-52824 -u https://target

Template: Kimai <= 2.57.0 - Default APP_SECRET Authentication Bypass
Severity: critical
Impact: An unauthenticated remote attacker can forge valid login-link URLs to authenticate as any user (including administrators) without knowing their password, achieving full account takeover.
Remediation: Upgrade to Kimai >= 2.58.0 which generates a random APP_SECRET on first boot. Alternatively, manually set a unique APP_SECRET in your .env.local file.

Template by ProjectDiscovery nuclei-templates (DhiyaneshDK), MIT licensed. View the full template. Scan only systems you are authorised to test.

Frequently Asked Questions

### Summary The official Kimai Docker image ships with `APP_SECRET=change_this_to_something_unique` as the default environment variable. The Docker entrypoint does not override or validate this value. Any Kimai instance deployed using the Docker image without explicitly setting `APP_SECRET` runs with a publicly-known Symfony `kernel.secret`, enabling an unauthenticated attacker to forge HMAC-signed cookies and login links to take over any account including super_admin. ### Details `Dockerfile:263` sets `ENV APP_SECRET=change_this_to_something_unique`. This value is consumed by `config/packa

O3 Security · Impact-Aware SCA

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