CVE-2026-92128

The Jenkins Script Security Plugin, version 1415.v9a_f9b_3a_c253d and earlier, downloads a JAR file specified by URL twice when validating classpath entries: it confirms the sandbox approval against the first download but loads the classpath entries from the second. An attacker with permission to define classpath entries (for example, a user able to configure sandboxed scripts) can exploit this time-of-check/time-of-use gap by serving benign content for the approval fetch and malicious code for the load. Successful exploitation allows arbitrary code execution in the context of the Jenkins controller JVM, which typically means full compromise of the controller, its builds, and its stored credentials. Any Jenkins controller running an affected version of the plugin is exposed, though the attack requires low-privileged authenticated access and a high-complexity race between the two downloads. No public proof-of-concept or confirmed in-the-wild exploitation is currently known, and the issue is not listed in CISA KEV.

What to do: Upgrade the Script Security Plugin to the latest release in the Jenkins update center (any version newer than 1415.v9a_f9b_3a_c253d). In the interim, restrict which users may define classpath entries or run sandboxed scripts (e.g., limit Job/Configure permissions and review script-approval settings), and audit existing classpath entries for URLs pointing to attacker-controllable hosts.