{"@context":"https://openvex.dev/ns/v0.2.0","@id":"https://database.harborguard.co/cve/CVE-2026-7838/vex.json","author":"HarborGuard Database","role":"Document Creator","timestamp":"2026-07-01T03:33:26.501Z","version":1,"tooling":"HarborGuard Database (https://database.harborguard.co)","statements":[{"vulnerability":{"name":"CVE-2026-7838","@id":"https://www.cve.org/CVERecord?id=CVE-2026-7838","description":"UltraVNC viewer through 1.8.2.2 contains an integer overflow leading to a heap buffer overflow in the RFB protocol failure-response parsing path. In vncviewer/ClientConnection.cpp, the 4-byte network-supplied reasonLen field (type CARD32) is passed as reasonLen+1 to CheckBufferSize(). Because both operands are unsigned 32-bit, a reasonLen of 0xFFFFFFFF overflows to 0, causing CheckBufferSize to allocate only 256 bytes. The subsequent ReadString(m_netbuf, reasonLen) call then performs ReadExact f"},"products":[{"@id":"cpe:2.3:a:uvnc:ultravnc:*:*:*:*:*:*:*:*","identifiers":{"cpe23":"cpe:2.3:a:uvnc:ultravnc:*:*:*:*:*:*:*:*"}}],"status":"affected","action_statement":"No fixed version is published yet; monitor the upstream advisory.","timestamp":"2026-07-01T03:33:26.501Z"}]}