CVE-2023-21529CISA KEV

Microsoft Exchange Server Deserialization of Untrusted Data Vulnerability

Severity unknownCVSS unknownCheck the vendor advisory for fixed versions

CISA lists this Microsoft vulnerability as known exploited. Its MSRC release detail is outside this installation's collected history.

CISA KEV Check MSRC

CISA catalog record

Microsoft Exchange Server contains a deserialization of untrusted data that allows an authenticated attacker to achieve remote code execution.

Product: Exchange Server
Added to KEV: 13 Apr 2026
Federal remediation due: 27 Apr 2026
Known ransomware use: Yes

Page history

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Field-level log (2)

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23 Oct 2026 · 09:33:49 UTC Source coverage: cisa-kevIncomplete → Current
23 Oct 2026 · 08:31:50 UTC Source coverage: cisa-kevCurrent → Incomplete

Explore global source statements, affected packages and advisory history for CVE-2023-21529. The catalog has a separate collection scope from Microsoft release records.

More advisories, affected versions and source history

cve-program · CVE-2023-21529

Published

Microsoft Exchange Server 2013 Cumulative Update 23

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "vendor": "Microsoft",
                    "product": "Microsoft Exchange Server 2013 Cumulative Update 23",
                    "platforms": [
                        "x64-based Systems"
                    ],
                    "versions": [
                        {
                            "version": "15.00.0",
                            "lessThan": "15.00.1497.047",
                            "versionType": "custom",
                            "status": "affected"
                        }
                    ]
                }

Microsoft Exchange Server 2016 Cumulative Update 23

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "vendor": "Microsoft",
                    "product": "Microsoft Exchange Server 2016 Cumulative Update 23",
                    "platforms": [
                        "x64-based Systems"
                    ],
                    "versions": [
                        {
                            "version": "15.01.0",
                            "lessThan": "15.01.2507.021",
                            "versionType": "custom",
                            "status": "affected"
                        }
                    ]
                }

Microsoft Exchange Server 2019 Cumulative Update 11

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "vendor": "Microsoft",
                    "product": "Microsoft Exchange Server 2019 Cumulative Update 11",
                    "platforms": [
                        "x64-based Systems"
                    ],
                    "versions": [
                        {
                            "version": "15.02.0",
                            "lessThan": "15.02.0986.041",
                            "versionType": "custom",
                            "status": "affected"
                        }
                    ]
                }

Microsoft Exchange Server 2019 Cumulative Update 12

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "vendor": "Microsoft",
                    "product": "Microsoft Exchange Server 2019 Cumulative Update 12",
                    "platforms": [
                        "x64-based Systems"
                    ],
                    "versions": [
                        {
                            "version": "15.02.0",
                            "lessThan": "15.02.1118.025",
                            "versionType": "custom",
                            "status": "affected"
                        }
                    ]
                }

Original source record · Cite this exact observation · Complete original publisher JSON