Summary
Insufficient Session Expiration after a password change
TL;DR
This vulnerability 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.
Introduction
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 or browser even if the logged in user has since changed their password.
Credits
Thanks to Shankar Acharya (@5hank4r) for responsibly reporting the identified issue.
Impact
Kirby did not invalidate old user sessions after the user password was 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.
CVE-2023-38489 has a CVSS score of 7.3 (High). The vector is network-reachable, low privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, 3.9.6); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
The problem has been patched in Kirby 3.5.8.3, Kirby 3.6.6.3, Kirby 3.7.5.2, Kirby 3.8.4.1 and Kirby 3.9.6. Please update to one of these or a later version to fix the vulnerability.
In all of the mentioned releases, we have updated the authentication implementation to keep track of the last time the password was changed. If a new password was set 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.
Frequently Asked Questions
- What is CVE-2023-38489? CVE-2023-38489 is a high-severity security vulnerability in getkirby/cms (composer), affecting versions < 3.5.8.3. It is fixed in 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, 3.9.6.
- How severe is CVE-2023-38489? CVE-2023-38489 has a CVSS score of 7.3 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of getkirby/cms are affected by CVE-2023-38489? getkirby/cms (composer) versions < 3.5.8.3 is affected.
- Is there a fix for CVE-2023-38489? Yes. CVE-2023-38489 is fixed in 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, 3.9.6. Upgrade to this version or later.
- Is CVE-2023-38489 exploitable, and should I be worried? Whether CVE-2023-38489 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2023-38489 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2023-38489?
- Upgrade
getkirby/cmsto 3.5.8.3 or later - Upgrade
getkirby/cmsto 3.6.6.3 or later - Upgrade
getkirby/cmsto 3.7.5.2 or later - Upgrade
getkirby/cmsto 3.8.4.1 or later - Upgrade
getkirby/cmsto 3.9.6 or later
- Upgrade