CVE-2020-12820

HIGHCVSS 8.8/10EPSS 0.86%

Last modified

CVE-2020-12820 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. Under non-default configuration, a stack-based buffer overflow in FortiOS version 6.0.10 and below, version 5.6.12 and below may allow a remote attacker authenticated to the SSL VPN to crash the FortiClient NAC daemon (fcnacd) and potentially execute arbitrary code via requesting a large FortiClient file name. We are not aware of proof of concept code successfully achieving the latter.. EPSS estimates a 0.86% chance of exploitation in the next 30 days.

Description

Under non-default configuration, a stack-based buffer overflow in FortiOS version 6.0.10 and below, version 5.6.12 and below may allow a remote attacker authenticated to the SSL VPN to crash the FortiClient NAC daemon (fcnacd) and potentially execute arbitrary code via requesting a large FortiClient file name. We are not aware of proof of concept code successfully achieving the latter.

Metrics

CVSS 3.1
8.8/10

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

EPSS Probability
0.86%

53.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
FortinetFortios< 5.6.13
FortinetFortios>= 6.0.0, < 6.0.11

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2020-12820?
Under non-default configuration, a stack-based buffer overflow in FortiOS version 6.0.10 and below, version 5.6.12 and below may allow a remote attacker authenticated to the SSL VPN to crash the FortiClient NAC daemon (fcnacd) and potentially execute arbitrary code via requesting a large FortiClient file name. We are not aware of proof of concept code successfully achieving the latter.
How severe is CVE-2020-12820?
CVE-2020-12820 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 0.86% probability of exploitation in the next 30 days.
How do I fix CVE-2020-12820?
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-2020-12820?

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

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Source: NVD / NIST