Improper input validation in Realvnc Vnc Viewer

CVE-2021-41380

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

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.010 (60.1th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 60th percentile — 60.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2021-41380: held from 0.010 to 0.010.

EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: 0.000

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2021-41380?
CVE-2021-41380 is a medium-severity vulnerability in Realvnc Vnc Viewer, classified under Improper Input Validation. CVSS score: 6.5/10. Published 2021-09-17.
How severe is CVE-2021-41380?
Medium severity. CVSS v3 base score is 6.5 out of 10.
Is CVE-2021-41380 known to be exploited?
3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.