JetBrains IntelliJ IDEA CVE-2026-100256

Exploitation requires the victim to open an attacker-supplied 'untrusted' project in IntelliJ IDEA before 2026.2.3, where malicious Structural Search script constraints then execute code. Limiting factors: the attack is local (AV:L) and requires user interaction (UI:R) - the developer must actively open the malicious project; it does not work remotely over the network without that action. No authentication on the target is needed (PR:N), and default configurations are affected once an untrusted project is opened, but social-engineering the victim into opening the project is a practical prerequisite.

This is a genuine code-execution flaw (CWE-829, inclusion of functionality from an untrusted control sphere) but its real-world risk is moderate and gated by the local attack vector. The CVSS 3.1 vector (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H = 7.8) tells a consistent story: exploitation is not remote-over-network but requires a victim developer to open an attacker-supplied ('untrusted') project in IntelliJ IDEA (UI:R), after which Structural Search script constraints execute attacker-controlled code with full C/I/A impact in the user's context. PR:N is correct because the attacker needs no credentials on the target - they only need to get their malicious project opened. There is no EPSS score, no CISA KEV listing, and no public POC referenced, so this is no public exploit identified at time of analysis rather than an actively exploited threat. The 7.8 is driven by triple-High impact, not by ease of mass exploitation; the local vector plus required user interaction meaningfully lowers practical risk versus a network-reachable RCE. Note also that the input Tag 'Information Disclosure' contradicts the description, which describes RCE with full integrity/availability impact - the tag appears mislabeled.

An attacker crafts a malicious project (e.g., distributed via a repository, sample, or supply-chain lure) containing Structural Search script constraints that execute arbitrary code. A developer clones and opens it in a vulnerable IntelliJ IDEA (before 2026.2.3) in an untrusted context, and the script constraints run, giving the attacker code execution in the developer's session. No public exploit code has been identified at time of analysis.