CVE-2023-41041 is a low-severity (CVSS 2.6) CWE-613 vulnerability in org.graylog2:graylog2-server. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for org.graylog2:graylog2-server — see the affected versions and patch details below.
User session is still usable after logout in graylog2-server
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-41041.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
org.graylog2:graylog2-server☕org.graylog2:graylog2-serverReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Summary
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.graylog2:graylog2-server | ≥ 1.0&&< 5.0.9 | 5.0.9org.graylog2:graylog2-server:5.0.9 |
| ☕Maven | org.graylog2:graylog2-server | ≥ 5.1.0&&< 5.1.3 | 5.1.3org.graylog2:graylog2-server:5.1.3 |
Affected Products
grayloggraylogResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.graylog2:graylog2-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.graylog2:graylog2-server to 5.0.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-41041 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is CVE-2023-41041 in your dependencies?
Find it across Maven, including transitive dependencies.