Summary
Graylog user session is still usable after logout
In a multi-node Graylog cluster, after a user has explicitly logged out, a user session may still be used for API requests until it has reached its original expiry time.
Details
Each node maintains an in-memory cache of user sessions. Upon a cache-miss, the session is loaded from the database. After that, the node operates solely on the cached session. Modifications to sessions will update the cached version as well as the session persisted in the database. However, each node maintains their isolated version of the session.
When the user logs out, the session is removed from the node-local cache and deleted from the database. The other nodes will however still use the cached session.
These nodes will only fail to accept the session id if they intent to update the session in the database. They will then notice that the session is gone. This is true for most API requests originating from user interaction with the Graylog UI because these will lead to an update of the session's "last access" timestamp.
If the session update is however prevented by setting the X-Graylog-No-Session-Extension:true header in the request, the node will consider the (cached) session valid until the session is expired according to its timeout setting.
PoC
In a 2-node setup, with both nodes behind a load balancer:
- Log in
- Extract the session ID from the cookie
- Log out and close the browser
- Perform the following API request repeatedly with curl (with
<session-id>replaced with the session id from step 2 and<lb-host>replaced with the hostname of your load balancer):curl -I -H X-Graylog-No-Session-Extension:true https://<session-id>:session@<lb-host>/api/system/cluster/nodes - Notice that the request is sometimes rejected, but sometimes succeeds
Impact
No session identifiers are leaked.
After a user has logged out, the UI shows the login screen again, which gives the user the impression that their session is not valid anymore. However, if the session becomes compromised later, it can still be used to perform API requests against the Graylog cluster. The time frame for this is limited to the configured session lifetime, starting from the time when the user logged out.
CVE-2023-41041 has a CVSS score of 2.6 (Low). 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 (5.0.9, 5.1.3); 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.
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org.graylog2:graylog2-server to 5.0.9 or later; org.graylog2:graylog2-server to 5.1.3 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2023-41041? CVE-2023-41041 is a low-severity security vulnerability in org.graylog2:graylog2-server (maven), affecting versions >= 1.0, < 5.0.9. It is fixed in 5.0.9, 5.1.3.
- How severe is CVE-2023-41041? CVE-2023-41041 has a CVSS score of 2.6 (Low). 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 org.graylog2:graylog2-server are affected by CVE-2023-41041? org.graylog2:graylog2-server (maven) versions >= 1.0, < 5.0.9 is affected.
- Is there a fix for CVE-2023-41041? Yes. CVE-2023-41041 is fixed in 5.0.9, 5.1.3. Upgrade to this version or later.
- Is CVE-2023-41041 exploitable, and should I be worried? Whether CVE-2023-41041 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-2023-41041 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-2023-41041?
- Upgrade
org.graylog2:graylog2-serverto 5.0.9 or later - Upgrade
org.graylog2:graylog2-serverto 5.1.3 or later
- Upgrade