Apache Syncope CVE-2026-42782

Exploitation requires an authenticated administrator who holds the entitlements to manage Implementations (PR:H in the CVSS vector confirms high-privilege access); it is not reachable by unauthenticated or low-privileged users. The specific technical condition is placing untrusted code in a Groovy class static initializer, which reaches a non-sandboxed execution path that ordinary sandboxed Groovy code does not. No end-user interaction is needed (UI:N) and the attack is network-reachable to the admin interface (AV:N). The principal limiting factor is the trusted-admin prerequisite plus the requirement that the target run an affected version (3.0-3.0.16, 4.0-4.0.5, or 4.1.0); environments restricting the Implementations entitlement materially reduce who can trigger this.

The CVSS 3.1 vector (AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H, base 7.2) shows network-reachable, low-complexity exploitation with no user interaction, but PR:H is the decisive limiting factor: the attacker must already be an authenticated administrator with Implementations entitlements - a highly trusted role. The C:H/I:H/A:H trio reflects effective code execution within the Syncope process context once the sandbox is bypassed. EPSS is very low (0.02%, 6th percentile) and there is no KEV listing and no public exploit identified, so this is not currently a widespread, opportunistically exploited bug. Net assessment: a real and serious issue for the threat model of a malicious or compromised admin account (sandbox escape defeats a security control by design), but a comparatively low priority for environments where Implementations entitlements are tightly held and admin accounts are well protected. Note one tagging inconsistency: the input Tags label this 'Information Disclosure,' whereas the CVSS vector and description indicate full code execution impact (I:H/A:H), so the impact is broader than disclosure alone - treat the CVSS vector as authoritative.

A malicious insider - or an attacker who has compromised an administrator account with Implementations entitlements - creates a new Groovy Implementation whose payload lives in the class static initializer. When Syncope loads the class, the initializer runs outside the sandbox, executing arbitrary attacker code in the Syncope context to read secrets, alter identity data, or disrupt the service. No public exploit code has been identified, and exploitation requires the high-privilege admin access reflected by PR:H in the CVSS vector.