Microsoft Windows up to Server 2025 DHCP Server memory corruption

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.
7.1$5k-$25k0.48+

Summaryinfo

A vulnerability was found in Microsoft Windows up to Server 2025 and classified as very critical. The affected element is an unknown function of the component DHCP Server. The manipulation results in memory corruption. This vulnerability is identified as CVE-2026-77891. The attack is only possible with local access. There is not any exploit available. It is best practice to apply a patch to resolve this issue.

Detailsinfo

A vulnerability, which was classified as very critical, was found in Microsoft Windows up to Server 2025. Affected is an unknown code of the component DHCP Server. The manipulation with an unknown input leads to a memory corruption vulnerability. CWE is classifying the issue as CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

Out-of-bounds read in Windows DHCP Server allows an authorized attacker to execute code locally.

The advisory is available at msrc.microsoft.com. This vulnerability is traded as CVE-2026-77891 since 08/21/2026. The exploitability is told to be easy. Local access is required to approach this attack. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 09/09/2026).

Applying a patch is able to eliminate this problem.

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Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.1

VulDB Base Score: 8.2
VulDB Temp Score: 7.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 6.4
CNA Vector (microsoft): 🔒

CVSSv2info

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

Exploitinginfo

Class: Memory corruption
CWE: CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔒

Timelineinfo

08/21/2026 CVE reserved
09/09/2026 +19 days Advisory disclosed
09/09/2026 +0 days VulDB entry created
09/09/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: microsoft.com
Product: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2026-77891 (🔒)
GCVE (CVE): GCVE-0-2026-77891
GCVE (VulDB): GCVE-100-401286
scip Labs: https://www.scip.ch/en/?labs.20161215

Entryinfo

Created: 09/09/2026 04:53
Changes: 09/09/2026 04:53 (63)
Complete: 🔍
Cache ID: 216::103

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