CVE-2019-3973

CVE-2019-3973 is a medium-severity vulnerability in Comodo Antivirus with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.

Key facts

Description

Comodo Antivirus versions 11.0.0.6582 and below are vulnerable to Denial of Service affecting CmdGuard.sys via its filter port "cmdServicePort". A low privileged process can crash CmdVirth.exe to decrease the port's connection count followed by process hollowing a CmdVirth.exe instance with malicious code to obtain a handle to "cmdServicePort". Once this occurs, a specially crafted message can be sent to "cmdServicePort" using "FilterSendMessage" API. This can trigger an out-of-bounds write if lpOutBuffer parameter in FilterSendMessage API is near the end of specified buffer bounds. The crash occurs when the driver performs a memset operation which uses a size beyond the size of buffer specified, causing kernel crash.

Frequently asked questions

What is CVE-2019-3973?
Comodo Antivirus versions 11.0.0.6582 and below are vulnerable to Denial of Service affecting CmdGuard.sys via its filter port "cmdServicePort". A low privileged process can crash CmdVirth.exe to decrease the port's connection count followed by process hollowing a CmdVirth.exe instance with malicious code to obtain a handle to "cmdServicePort". Once this occurs, a specially crafted message can be sent to "cmdServicePort" using "FilterSendMessage" API. This can trigger an out-of-bounds write if lpOutBuffer parameter in FilterSendMessage API is near the end of specified buffer bounds. The crash occurs when the driver performs a memset operation which uses a size beyond the size of buffer specified, causing kernel crash.
How severe is CVE-2019-3973?
CVE-2019-3973 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2019-3973 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-3973?
CVE-2019-3973 affects Comodo Antivirus. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2019-3973?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2019-3973 published?
CVE-2019-3973 was published on 2019-07-17 and last updated on 2026-06-17.

References

Affected products (1)

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