점검 대응높음KEV 미등록
CVE-2026-7838
uvnc UltraVNC, ultravnc 취약점
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 for the original 4 GiB length into that 256-byte heap buffer. This overflow is reachable via rfbCo...
- 대응 우선순위
- 점검
- CVSS
- 8.7
- EPSS
- 1.40% 백분위 69.5% · 2026.07.15 기준
- CISA KEV
- 미등록
- 조치 기한
- -
- 공개일
- 2026.07.01