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CVE-2021-41380

MEDIUMCVSS 6.5/10EPSS 0.93%

Last modified

CVE-2021-41380 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. 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. EPSS estimates a 0.93% chance of exploitation in the next 30 days.

Description

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

Metrics

CVSS 3.1
6.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS Probability
0.93%

55.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
RealvncVnc Viewer6.21.406

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is 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
How severe is CVE-2021-41380?
CVE-2021-41380 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.93% probability of exploitation in the next 30 days.
How do I fix CVE-2021-41380?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-41380?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST