CVE-2023-38489
HIGHKirby vulnerable to Insufficient Session Expiration after a password change
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
getkirby/cms🐘getkirby/cms🐘getkirby/cms🐘getkirby/cms🐘getkirby/cmsReal-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
Kirby is a content management system. A vulnerability in versions prior to 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, and 3.9.6 affects all Kirby sites with user accounts (unless Kirby's API and Panel are disabled in the config). It can only be abused if a Kirby user is logged in on a device or browser that is shared with potentially untrusted users or if an attacker already maliciously used a previous password to log in to a Kirby site as the affected user.
Insufficient Session Expiration is when a web site permits an attacker to reuse old session credentials or session IDs for authorization. In the variation described in this advisory, it allows attackers to stay logged in to a Kirby site on another device even if the logged in user has since changed their password. Kirby did not invalidate user sessions that were created with a password that was since changed by the user or by a site admin. If a user changed their password to lock out an attacker who was already in possession of the previous password or of a login session on another device or browser, the attacker would not be reliably prevented from accessing the Kirby site as the affected user.
The problem has been patched in Kirby 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, and 3.9.6. In all of the mentioned releases, the maintainers have updated the authentication implementation to keep track of the hashed password in each active session. If the password changed since the login, the session is invalidated. To enforce this fix even if the vulnerability was previously abused, all users are logged out from the Kirby site after updating to one of the patched releases.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | getkirby/cms | all versions | 3.5.8.3 |
| 🐘Packagist | getkirby/cms | ≥ 3.6.0&&< 3.6.6.3 | 3.6.6.3 |
| 🐘Packagist | getkirby/cms | ≥ 3.7.0&&< 3.7.5.2 | 3.7.5.2 |
| 🐘Packagist | getkirby/cms | ≥ 3.8.0&&< 3.8.4.1 | 3.8.4.1 |
| 🐘Packagist | getkirby/cms | ≥ 3.9.0&&< 3.9.6 | 3.9.6 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for getkirby/cms. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update getkirby/cms to 3.5.8.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-38489 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 O3 protects you
O3 pinpoints whether CVE-2023-38489 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2023-38489. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-38489 in your dependencies?
O3 detects CVE-2023-38489 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.