CVE-2021-41380
MEDIUMRealVNC Viewer 6.21.406 - Denial of Service via Crafted RFB Protocol Data
Title source: llmDescription
RealVNC Viewer 6.21.406 allows remote VNC servers to cause a denial of service (application crash) via crafted RFB protocol data. NOTE: It is asserted that this issue requires social engineering a user into connecting to a fake VNC Server. The VNC Viewer application they are using will then hang, until terminated, but no memory leak occurs - the resources are freed once the hung process is terminated and the resource usage is constant during the hang. Only the process that is connected to the fake Server is affected. This is an application bug, not a security issue
References (1)
Core 1
Core References
Exploit, Third Party Advisory x_refsource_misc
https://gist.github.com/totaam/a90f2bb40f5b693ccec0ae903d021b03
Scores
CVSS v3
6.5
EPSS
0.0093
EPSS Percentile
56.0%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Details
CWE
CWE-20
Status
published
Products (1)
realvnc/vnc_viewer
6.21.406
Published
Sep 17, 2021
Tracked Since
Feb 18, 2026