Microsoft Exchange Server Remote Code Execution Vulnerability

Description

References

• msrc.microsoft.com/update-guide/vulnerability/CVE-2021-42321 · Patch
• packetstormsecurity.com/files/166153/Microsoft-Exchange-Server-Remote-Code-Execution.html · Exploit
• packetstormsecurity.com/files/168131/Microsoft-Exchange-Server-ChainedSerializationBinder-Remote-Code-Execution.html · Exploit
• portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42321 · Patch
• cisa.gov/known-exploited-vulnerabilities-catalog · US Government Resource
• CISA KEV · CVE-2021-42321

More vulnerabilities in exchange server

• CVE-2026-87696HIGH 7.5Improper verification of cryptographic signature in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a net…
• CVE-2026-87695HIGH 7.8Inclusion of functionality from untrusted control sphere in Microsoft Exchange Server allows an authorized attacker to elevate privileges lo…
• CVE-2026-87692HIGH 7.8Deserialization of untrusted data in Microsoft Exchange Server allows an authorized attacker to elevate privileges locally.
• CVE-2026-96940HIGH 8.8Weak authentication in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.
• CVE-2026-69641CRITICAL 9.1Missing authorization in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.