csirt@kutim:~/threat-intel/cve/CVE-2026-7840

Katalog CVE

CVSS 9.8 · Critical EPSS 2,6%

Kerentanan Out-of-bounds Write pada uvnc ultravnc. Skor CVSS 3.1 9.8 (Critical) menurut CNA.

Deskripsi (NVD)

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 by at least 500 bytes with a single HTTP request containing a URI of 1500 bytes or longer, corrupting adjacent .bss-segment globals. The overflow occurs before any authentication check, making it reachable without credentials. A remote, unauthenticated attacker can achieve arbitrary code execution on the host running the repeater.

Rincian

Terbit di NVD
1 Juli 2026
Terakhir diubah
9 Juli 2026
Status NVD
Modified
CVSS 3.1
9.8 (Critical), sumber CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H · uraikan di kalkulator
Jenis kelemahan (CWE)
CWE-787: Out-of-bounds Write
EPSS (30 hari)
2,6% peluang dieksploitasi; lebih tinggi dari 85,1% CVE lain

Produk dan versi terdampak

VendorProdukVersi terdampak
uvnc ultravnc Semua versi hingga 1.8.2.2

> Data dari konfigurasi CPE di NVD.

Referensi dan perbaikan

Sumber: NVD · CVE.org · EPSS. Halaman ini disusun otomatis dari data tersebut; pembaruan terakhir 5 Okt 2026, 20:11 WITA. Kalau sistem di Perangkat Daerah memakai produk ini dan butuh bantuan, laporkan lewat kanal pelaporan.