Summary
Jenkins shows various technical details about the current user on the /whoAmI page. In a previous fix, the Cookie header value containing the HTTP session ID was redacted. However, user metadata shown on this page could also include the HTTP session ID in Jenkins 2.218 and earlier, LTS 2.204.1 and earlier.
This allows attackers able to exploit a cross-site scripting vulnerability to obtain the HTTP session ID value from this page.
Jenkins 2.219, LTS 2.204.2 no longer prints out the affected user metadata that might contain the HTTP session ID.
Additionally, we also redact values of further authentication-related HTTP headers in addition to Cookie on this page as a hardening.
Impact
CVE-2020-2103 has a CVSS score of 5.4 (Medium). 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 (2.219, 2.204.2); 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.
Remediation advice
org.jenkins-ci.main:jenkins-core to 2.219 or later; org.jenkins-ci.main:jenkins-core to 2.204.2 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2020-2103? CVE-2020-2103 is a medium-severity security vulnerability in org.jenkins-ci.main:jenkins-core (maven), affecting versions >= 2.205, < 2.219. It is fixed in 2.219, 2.204.2.
- How severe is CVE-2020-2103? CVE-2020-2103 has a CVSS score of 5.4 (Medium). 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.jenkins-ci.main:jenkins-core are affected by CVE-2020-2103? org.jenkins-ci.main:jenkins-core (maven) versions >= 2.205, < 2.219 is affected.
- Is there a fix for CVE-2020-2103? Yes. CVE-2020-2103 is fixed in 2.219, 2.204.2. Upgrade to this version or later.
- Is CVE-2020-2103 exploitable, and should I be worried? Whether CVE-2020-2103 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-2020-2103 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-2020-2103?
- Upgrade
org.jenkins-ci.main:jenkins-coreto 2.219 or later - Upgrade
org.jenkins-ci.main:jenkins-coreto 2.204.2 or later
- Upgrade