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.

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)

EPSS: 0.010 (57.8th percentile) — read the EPSS interpretation.

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.

Affected products

Realvnc Vnc_viewer — versions 6.21.406
N/a — versions n/a

Weakness classification (CWE)

CWE-20 — Improper Input Validation

Public proof-of-concept exploits

References

cve@mitre.org (Exploit, Third Party Advisory, x_refsource_MISC)

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.