Coverage › CVE-2023-21529
CVE-2023-21529 Unmapped
Microsoft Exchange Server Deserialization of Untrusted Data Vulnerability
- Vendor / product
- Microsoft — Exchange Server
- Description (CISA)
- Microsoft Exchange Server contains a deserialization of untrusted data that allows an authenticated attacker to achieve remote code execution.
- Added to KEV
- 2026-04-13 — after the latest CTID mapping snapshot (2025-07-28)
- Due date
- 2026-04-27
- Required action
- Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- Known ransomware use
- Known
- CWE
- CWE-502
- CISA notes
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21529
https://nvd.nist.gov/vuln/detail/CVE-2023-21529 - Elsewhere
- cve.org · NVD · CISA KEV · JSON
ATT&CK techniques
No public source states how this vulnerability is exploited in ATT&CK terms.
The only authoritative CVE → ATT&CK mapping in the open — CTID's Mappings Explorer, pinned to a KEV snapshot of 2025-07-28 and ATT&CK 16.1 — does not include CVE-2023-21529. This entry was added to KEV on 2026-04-13, after that snapshot; of the 283 entries added since, 0 have a mapping. CISA's catalogue carries no technique field. kevmap does not infer techniques from the CWE (CWE-502) — here is why — and does not guess.
This page will change state automatically if a mapping is published. What is shown above is everything CISA publishes about the entry.