VDB-220957 · CVE-2023-21529 · GCVE-0-2023-21529

Microsoft Exchange Server 2013 CU23/2016 CU23/2019 CU11/2019 CU12 deserialization

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
8.3	$5k-$25k	0.00

Summaryinfo

A vulnerability identified as very critical has been detected in Microsoft Exchange Server 2013 CU23/2016 CU23/2019 CU11/2019 CU12. Affected by this vulnerability is an unknown functionality. This manipulation causes an unknown weakness. This vulnerability is tracked as CVE-2023-21529. The attack is possible to be carried out remotely. Moreover, an exploit is present. Applying a patch is the recommended action to fix this issue.

Detailsinfo

A vulnerability was found in Microsoft Exchange Server 2013 CU23/2016 CU23/2019 CU11/2019 CU12 (Groupware Software). It has been declared as very critical. The CWE definition for the vulnerability is CWE-502. The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid. As an impact it is known to affect confidentiality, integrity, and availability.

The weakness was disclosed 02/14/2023 as confirmed security guidance (Website). The advisory is shared at portal.msrc.microsoft.com. This vulnerability is known as CVE-2023-21529. Technical details are unknown but an exploit is available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 04/21/2026).

It is declared as attacked. The CISA Known Exploited Vulnerabilities Catalog lists this issue since 04/13/2026 with a due date of 04/27/2026:

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Applying a patch is able to eliminate this problem. A possible mitigation has been published immediately after the disclosure of the vulnerability.

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

Groupware Software

Vendor

Microsoft

Name

Exchange Server

Version

License

commercial

Website

Vendor: https://www.microsoft.com/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.8
VulDB Meta Temp Score: 8.3

VulDB Base Score: 8.8
VulDB Temp Score: 8.4
VulDB Vector: 🔍
VulDB Reliability: 🔍

Vendor Base Score (Microsoft): 8.8
Vendor Vector (Microsoft): 🔍

CNA Base Score: 8.8
CNA Vector (Microsoft): 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Deserialization
CWE: CWE-502 / CWE-20
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Attacked

EPSS Score: 🔍
EPSS Percentile: 🔍

KEV Added: 🔍
KEV Due: 🔍
KEV Remediation: 🔍
KEV Ransomware: 🔍
KEV Notice: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍

Timelineinfo

12/01/2022 🔍
02/14/2023 +75 days 🔍
02/14/2023 +0 days 🔍
02/14/2023 +0 days 🔍
04/21/2026 +1162 days 🔍

Sourcesinfo

Vendor: microsoft.com

Advisory: portal.msrc.microsoft.com
Status: Confirmed

CVE: CVE-2023-21529 (🔍)
GCVE (CVE): GCVE-0-2023-21529
GCVE (VulDB): GCVE-100-220957
scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 02/14/2023 19:29
Updated: 04/21/2026 22:06
Changes: 02/14/2023 19:29 (34), 02/14/2023 19:33 (19), 03/15/2023 08:39 (2), 04/13/2026 20:42 (29), 04/14/2026 05:46 (12), 04/21/2026 22:06 (1)
Complete: 🔍
Cache ID: 216::103