CVE-2020-0796: Microsoft SMBv3 Remote Code Execution Vulnerability

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 10 Feb 2022, 700 days after the CVE record was published.

How likely is exploitation in the next 30 days?

99.8%

EPSS score, percentile 100 of all scored records

How severe?

10.0 Critical

CVSS v3.1 base score, from CISA's enrichment of the record

What should I do?

Required action (CISA), due 10 Aug 2022: Apply updates per vendor instructions.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected: unspecified; unspecified; unspecified; unspecified; unspecified; unspecified; unspecified; unspecified

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

What to do

CISA due date for this action: 10 August 2022.

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

Linked from CISA's catalog entry

• https://nvd.nist.gov/vuln/detail/CVE-2020-0796

Affected products and versions

As listed in the CVE record.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

About this vulnerability

A remote code execution vulnerability exists in the way that the Microsoft Server Message Block 3.1.1 (SMBv3) protocol handles certain requests. An attacker who successfully exploited the vulnerability could gain the ability to execute code on the target server or client.

Summary: CISA's KEV catalog, as of 28 Oct 2026.

• CISA added CVE-2020-0796 to its Known Exploited Vulnerabilities (KEV) catalog on 10 Feb 2022.
• CISA marks it as known to be used in ransomware campaigns.
• The due date CISA sets for the required action is 10 Aug 2022.
• The CVE record was published on 12 Mar 2020, 700 days before it was added to KEV.
• The CVE record carries a CVSS v3.1 base score of 10.0 (Critical), taken from CISA's enrichment of the record.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 99.8% (percentile 100), as of 28 Oct 2026.
• CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact total.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.

Description

A remote code execution vulnerability exists in the way that the Microsoft Server Message Block 3.1.1 (SMBv3) protocol handles certain requests, aka 'Windows SMBv3 Client/Server Remote Code Execution Vulnerability'.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

Weakness

• CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.

Timeline

References

• portal.msrc.microsoft.com
• packetstormsecurity.com
• packetstormsecurity.com
• packetstormsecurity.com
• packetstormsecurity.com
• packetstormsecurity.com
• packetstormsecurity.com

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