Microsoft Exchange Server incorrect implementation of authentication algorithm

CVSS Meta Temp Score
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Current Exploit Price (≈)
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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.
7.6$0-$5k0.00

Summaryinfo

A vulnerability was found in Microsoft Exchange Server. It has been classified as critical. Impacted is an unknown function. This manipulation causes incorrect implementation of authentication algorithm. This vulnerability appears as CVE-2025-53782. The attack requires local access. There is no available exploit. Applying a patch is the recommended action to fix this issue.

Detailsinfo

A vulnerability has been found in Microsoft Exchange Server (unknown version) and classified as critical. Affected by this vulnerability is an unknown code block. The manipulation with an unknown input leads to a incorrect implementation of authentication algorithm vulnerability. The CWE definition for the vulnerability is CWE-303. The requirements for the product dictate the use of an established authentication algorithm, but the implementation of the algorithm is incorrect. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Incorrect implementation of authentication algorithm in Microsoft Exchange Server allows an unauthorized attacker to elevate privileges locally.

The weakness was presented 10/14/2025 as confirmed security update guide (Website). The advisory is shared at msrc.microsoft.com. This vulnerability is known as CVE-2025-53782. The exploitation appears to be easy. An attack has to be approached locally. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 10/27/2025).

The vulnerability scanner Nessus provides a plugin with the ID 270373 (Security Updates for Microsoft Exchange Server (October 2025)), which helps to determine the existence of the flaw in a target environment.

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

The vulnerability is also documented in the vulnerability database at Tenable (270373). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

Vendor

Name

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.1
VulDB Meta Temp Score: 7.6

VulDB Base Score: 7.8
VulDB Temp Score: 6.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

Vendor Base Score (Microsoft): 8.4
Vendor Vector (Microsoft): 🔒

NVD Base Score: 7.8
NVD Vector: 🔒

CNA Base Score: 8.4
CNA Vector (Microsoft): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Incorrect implementation of authentication algorithm
CWE: CWE-303
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Unproven

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 270373
Nessus Name: Security Updates for Microsoft Exchange Server (October 2025)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Patch
Status: 🔍

Reaction Time: 🔒
0-Day Time: 🔒
Exposure Time: 🔒

Timelineinfo

10/14/2025 VulDB entry created
10/14/2025 +0 days Advisory disclosed
10/14/2025 +0 days Countermeasure disclosed
10/27/2025 +13 days VulDB entry last update

Sourcesinfo

Vendor: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2025-53782 (🔒)
GCVE (CVE): GCVE-0-2025-53782
GCVE (VulDB): GCVE-100-328333

Entryinfo

Created: 10/14/2025 19:13
Updated: 10/27/2025 21:31
Changes: 10/14/2025 19:13 (33), 10/14/2025 19:16 (35), 10/18/2025 23:06 (2), 10/27/2025 21:31 (20)
Complete: 🔍
Cache ID: 216::103

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

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