GHSA-jr9p-4h4j-6c58

Suggest an improvement
Source
https://github.com/advisories/GHSA-jr9p-4h4j-6c58
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-jr9p-4h4j-6c58/GHSA-jr9p-4h4j-6c58.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-jr9p-4h4j-6c58
Aliases
Published
2026-07-14T00:07:59Z
Modified
2026-07-14T00:26:47Z
Severity
  • 9.1 (Critical) CVSS_V4 - 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 CVSS Calculator
Summary
Kimai: Default APP_SECRET in Docker Image Enables Cookie Forgery and Account Takeover
Details

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.

Database specific 
{
    "cwe_ids":  [
        "CWE-1188"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2026-07-14T00:07:59Z",
    "nvd_published_at":  null,
    "severity":  "CRITICAL"
}
References

Affected packages

Packagist / kimai/kimai

Package

Name
kimai/kimai
Purl
pkg:composer/kimai/kimai

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
2.58.0

Affected versions

0.*
0.1
0.2
0.3
0.4
0.5
0.6
0.6.1
0.7
0.8
0.8.1
0.9
1.*
1.0
1.0.1
1.1
1.2
1.3
1.4
1.4.1
1.4.2
1.5
1.6
1.6.1
1.6.2
1.7
1.8
1.9
1.10
1.10.1
1.10.2
1.11
1.11.1
1.12
1.13
1.14
1.14.1
1.14.2
1.14.3
1.15
1.15.1
1.15.2
1.15.3
1.15.4
1.15.5
1.15.6
1.16
1.16.1
1.16.2
1.16.3
1.16.4
1.16.5
1.16.6
1.16.7
1.16.8
1.16.9
1.16.10
1.17
1.17.1
1.18
1.18.1
1.18.2
1.19
1.19.1
1.19.2
1.19.3
1.19.4
1.19.5
1.19.6
1.19.7
1.20
1.20.1
1.20.2
1.20.3
1.20.4
1.21.0
1.22.0
1.22.1
1.23.0
1.23.1
1.24.0
1.25.0
1.26.0
1.27.0
1.28.0
1.28.1
1.29.0
1.29.1
1.30.0
1.30.1
1.30.2
1.30.3
1.30.4
1.30.5
1.30.6
1.30.7
1.30.8
1.30.9
1.30.10
1.30.11
2.*
2.0.0-alpha
2.0.0-beta
2.0.0-beta-2
2.0.0-beta-3
2.0.0-rc-1
2.0.0
2.0.1
2.0.2
2.0.3
2.0.4
2.0.5
2.0.6
2.0.7
2.0.8
2.0.9
2.0.10
2.0.11
2.0.12
2.0.13
2.0.14
2.0.15
2.0.16
2.0.17
2.0.18
2.0.19
2.0.20
2.0.21
2.0.22
2.0.23
2.0.24
2.0.25
2.0.26
2.0.27
2.0.28
2.0.29
2.0.30
2.0.31
2.0.32
2.0.33
2.0.34
2.0.35
2.1.0
2.2.0
2.2.1
2.3.0
2.4.0
2.4.1
2.5.0
2.6.0
2.7.0
2.8.0
2.9.0
2.10.0
2.11.0
2.12.0
2.13.0
2.14.0
2.15.0
2.16.0
2.16.1
2.17.0
2.18.0
2.19.0
2.19.1
2.20.0
2.20.1
2.21.0
2.22.0
2.23.0
2.24.0
2.25.0
2.26.0
2.27.0
2.28.0
2.29.0
2.30.0
2.31.0
2.32.0
2.33.0
2.34.0
2.35.0
2.35.1
2.36.0
2.36.1
2.37.0
2.38.0
2.39.0
2.40.0
2.41.0
2.42.0
2.43.0
2.44.0
2.45.0
2.46.0
2.47.0
2.48.0
2.49.0
2.50.0
2.51.0
2.52.0
2.53.0
2.54.0
2.55.0
2.56.0
2.57.0

Database specific

last_known_affected_version_range 
"<= 2.57.0"
source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-jr9p-4h4j-6c58/GHSA-jr9p-4h4j-6c58.json"