Buffer Overflow Vulnerability in FortiOS Products

Summary

CVE-2020-12820 is a high-severity stack-based buffer overflow vulnerability in FortiOS versions 6.0.10 and earlier, as well as 5.6.12 and earlier. When non-default configurations are applied, an authenticated remote attacker exploiting this vulnerability through the SSL VPN can cause the FortiClient NAC daemon (fcnacd) to crash or, potentially, execute arbitrary code by sending a request with an excessively large FortiClient file name. Although there is currently no known proof of concept that successfully demonstrates remote code execution, the risk posed by this flaw warrants immediate attention and remediation measures.

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