CVE-2023-40343
MEDIUMCVE-2023-40343 is a medium-severity (CVSS 5.9) CWE-203 vulnerability in jenkins tuleap authentication. O3 Security detects and blocks CVE-2023-40343 exploitation at runtime via eBPF exploit-chain detection and L7 egress monitoring, even on unpatched systems.
Jenkins Tuleap Authentication Plugin 1.1.20 and earlier uses a non-constant time comparison function when validating an authentication token allowing attackers to use statistical methods…
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.
How urgent is this, really
CVE-2023-40343 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 356,453 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Description
Jenkins Tuleap Authentication Plugin 1.1.20 and earlier uses a non-constant time comparison function when validating an authentication token allowing attackers to use statistical methods to obtain a valid authentication token.
Affected Products
tuleap authenticationjenkinsDetection & mitigation playbook
Vendor / applianceDetect
Inventory every jenkins tuleap authentication deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for exploitation at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.
Remediation status
No patch has shipped for CVE-2023-40343 yet — track the jenkins tuleap authentication advisory for a fixed release and apply the workarounds below in the meantime.
Mitigate without a patch
Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.
How O3 protects you
O3 detects and blocks CVE-2023-40343 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.
Tailored to CVE-2023-40343. 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-2023-40343 being exploited in your environment?
O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2023-40343 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.