CVSS 3.7 · Low EPSS 0,49%
Kerentanan Off-by-one Error pada uvnc ultravnc. Skor CVSS 3.1 3.7 (Low) menurut NVD.
UltraVNC repeater through 1.8.2.2 contains an off-by-one error in the Base64 decode helper used for HTTP Basic authentication. In repeater/webgui/webutils.c:817, the wi_uudecode() function checks whether the input length exceeds the output buffer with a strict greater-than comparison (>), while the correct check should be greater-than-or-equal (>=). When strlen(authdata) equals sizeof(decode), the decoded output length (approximately 3/4 of input) does not overflow the buffer in current practice because the outer HTTP request bounds constrain the Authorization header. However, the defective check leaves a latent off-by-one condition that could become exploitable if the buffering constraints change. The current risk is limited to a one-byte write at the boundary of a 1024-byte stack buffer under constrained conditions.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
· uraikan di kalkulator | Vendor | Produk | Versi terdampak |
|---|---|---|
| uvnc | ultravnc | Semua versi hingga 1.8.2.2 |