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

Vulnerability summary

CVE-2020-0796 is a critical (CVSS 10.0) vulnerability in Microsoft SMBv3. It is known to be exploited: CISA lists it, first on 10-02-2022. It has been used in ransomware campaigns. EPSS estimates a 99.81% chance of exploitation in the next 30 days, higher than 99.9% of scored vulnerabilities. 7 public exploits are recorded.

Timeline

1. 12-03-2020
   PublishedVulnerability first disclosed.
2. 10-02-2022
   Added to CISA KEVMicrosoft SMBv3 Remote Code Execution Vulnerability
3. 10-08-2022
   CISA remediation dueApply updates per vendor instructions.
4. 01-10-2026
   Last modifiedVulnerability information updated.

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'.

• CWE-119Improper Restriction of Operations within the Bounds of a Memory BufferThe product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.