Microsoft · MessagePack-CSharp Denial of Service Vulnerability
Affects MicrosoftSource GCVE Database
Not known to be exploited : upgrade to 9.0.21 when convenient.
Data as of 10 Nov 2026, 21:52 UTC
Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD
- Patch
- Available – fixed in 9.0.21
Exploitation evidence
Disclosed: evidence found.
CVE published 13 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 10 Nov 2026.
What to do
Upgrade Microsoft to 9.0.21.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Microsoft Security Response Center Microsoft | Affected
| Fixed in
|
AI-suggested
Upgrade to MessagePack-CSharp version 9.0.21 or later to remediate this vulnerability.
Description
A denial of service vulnerability exists in MessagePack-CSharp versions prior to 9.0.21. This issue has been addressed in version 9.0.21.