RTI Connext Professional EUVD-2026-84617

Requires LOCAL access to a host running RTI Connext Professional Core Libraries (AV:L) with an existing LOW-privileged authenticated context (PR:L), plus HIGH attack complexity (AC:H) meaning the attacker must satisfy specific, hard-to-control conditions to reliably wrap the vulnerable integer calculation. No user interaction is needed (UI:N). Exploitation is bounded to the affected version ranges: 7.4.0 up to (not including) 7.7.0.1, 7.0.0 up to 7.3.1.6, and the 6.1.0 6.1.x branch. The limiting factors - local-only vector, prerequisite low-privilege foothold, and non-trivial trigger conditions - mean this is realistically a post-compromise privilege/resource escalation on DDS-participant hosts rather than a remotely reachable flaw.

This is a genuine but access-gated issue, not a drop-everything remote emergency. The CVSS 4.0 vector (AV:L/AC:H/AT:N/PR:L/UI:N) is the critical distinguisher from the other RTI Connext advisories in this batch (CVE-2026-7866, -18457, -18459, -18461), which are all network-vector (AV:N) unauthenticated flaws - THIS one requires LOCAL access, LOW privileges, and HIGH attack complexity, materially lowering real-world exploitability despite the high VC/VI/VA impact triad. No EPSS score, no CISA KEV listing, and no public POC are provided, so exploitation status is 'no public exploit identified at time of analysis.' The 7.3 score is driven almost entirely by the full high-impact triad (VC:H/VI:H/VA:H via shared-resource manipulation), while the AC:H and AV:L metrics cap it below the network siblings. Net: a legitimate patch priority for defense/robotics/autonomous-systems operators running Connext, but real-world risk is constrained to attackers who already have a local low-privileged foothold and can meet the complex trigger conditions of an integer overflow - targeted post-compromise escalation rather than mass exploitation.

An attacker who already holds a low-privileged local account on a host running RTI Connext Professional crafts input that triggers an integer overflow (CWE-190) in the Core Libraries, wrapping a size/bounds calculation to manipulate a shared resource. Because the flaw combines the overflow with improper access control over that shared resource, successful exploitation can corrupt or hijack the resource to compromise confidentiality, integrity, and availability of the Connext process. No public exploit code is identified, and the AC:H rating indicates the overflow requires specific, hard-to-control conditions to trigger reliably.