{"id":"GHSA-jr9p-4h4j-6c58","summary":"Kimai: Default APP_SECRET in Docker Image Enables Cookie Forgery and Account Takeover","details":"### Summary\n\nThe 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.\n\n### Details\n\n`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:\n\n- The `KIMAI_REMEMBER` remember-me cookie\n- LoginLink signatures\n- Password reset URLs\n- CSRF tokens\n\nThe `.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.\n\nUser 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.\n\n*A PoC was provided, but removed for security reasons.*\n\n### Impact\n\nAny 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:\n- a username is known AND\n- the correct account ID for this username is guessed AND\n- the account has no active 2FA (two factor) authentication\n\n## Solution\n\n- 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`\n- 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\n- The documentation was updated to highlight the importance of using a random secret for `APP_SECRET`\n- The Dockerfile removed default `APP_SECRET=change_this_to_something_unique`\n- 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`\n\nSee [https://www.kimai.org/en/security/ghsa-jr9p-4h4j-6c58](https://www.kimai.org/en/security/ghsa-jr9p-4h4j-6c58) for more information.","aliases":["CVE-2026-52824"],"modified":"2026-07-14T00:26:47.189560Z","published":"2026-07-14T00:07:59Z","database_specific":{"severity":"CRITICAL","github_reviewed":true,"github_reviewed_at":"2026-07-14T00:07:59Z","nvd_published_at":null,"cwe_ids":["CWE-1188"]},"references":[{"type":"WEB","url":"https://github.com/kimai/kimai/security/advisories/GHSA-jr9p-4h4j-6c58"},{"type":"PACKAGE","url":"https://github.com/kimai/kimai"}],"affected":[{"package":{"name":"kimai/kimai","ecosystem":"Packagist","purl":"pkg:composer/kimai/kimai"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.58.0"}]}],"versions":["0.1","0.2","0.3","0.4","0.5","0.6","0.6.1","0.7","0.8","0.8.1","0.9","1.0","1.0.1","1.1","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","1.16.10","1.16.2","1.16.3","1.16.4","1.16.5","1.16.6","1.16.7","1.16.8","1.16.9","1.17","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","1.2","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","1.3","1.30.0","1.30.1","1.30.10","1.30.11","1.30.2","1.30.3","1.30.4","1.30.5","1.30.6","1.30.7","1.30.8","1.30.9","1.4","1.4.1","1.4.2","1.5","1.6","1.6.1","1.6.2","1.7","1.8","1.9","2.0.0","2.0.0-alpha","2.0.0-beta","2.0.0-beta-2","2.0.0-beta-3","2.0.0-rc-1","2.0.1","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","2.0.2","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","2.0.3","2.0.30","2.0.31","2.0.32","2.0.33","2.0.34","2.0.35","2.0.4","2.0.5","2.0.6","2.0.7","2.0.8","2.0.9","2.1.0","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","2.2.0","2.2.1","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","2.3.0","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","2.4.0","2.4.1","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","2.5.0","2.50.0","2.51.0","2.52.0","2.53.0","2.54.0","2.55.0","2.56.0","2.57.0","2.6.0","2.7.0","2.8.0","2.9.0"],"database_specific":{"last_known_affected_version_range":"\u003c= 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"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"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"}]}