{"@context":"https://openvex.dev/ns/v0.2.0","@id":"https://database.harborguard.co/cve/CVE-2026-7840/vex.json","author":"HarborGuard Database","role":"Document Creator","timestamp":"2026-07-01T03:33:28.957Z","version":1,"tooling":"HarborGuard Database (https://database.harborguard.co)","statements":[{"vulnerability":{"name":"CVE-2026-7840","@id":"https://www.cve.org/CVERecord?id=CVE-2026-7840","description":"UltraVNC repeater through 1.8.2.2 contains a global buffer overflow in its embedded HTTP administration server. The functions wi_senderr() and wi_replyhdr() in repeater/webgui/webutils.c write the caller-supplied HTTP request URI into a fixed 1000-byte global buffer (hdrbuf) via unchecked sprintf calls. The HTTP receive buffer accepts URIs up to approximately 150 KB (WI_RXBUFSIZE = 153600), so an unauthenticated attacker who can reach the repeater HTTP port (default TCP 80) can overflow hdrbuf b"},"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":"2026-07-01T03:33:28.957Z"}]}