Microsoft Office/Outlook heap-based overflow

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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8.4$5k-$25k0.45+

Summaryinfo

A vulnerability categorized as critical has been discovered in Microsoft Office and Outlook. Impacted is an unknown function. Such manipulation leads to heap-based overflow. This vulnerability is documented as CVE-2026-78509. The attack can be executed remotely. There is not any exploit available. Applying a patch is advised to resolve this issue.

Detailsinfo

A vulnerability was found in Microsoft Office and Outlook (affected version unknown) and classified as critical. Affected by this issue is an unknown functionality. The manipulation with an unknown input leads to a heap-based overflow vulnerability. Using CWE to declare the problem leads to CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). Impacted is confidentiality, integrity, and availability. CVE summarizes:

Heap-based buffer overflow in Microsoft Office Outlook allows an unauthorized attacker to execute code over a network.

The advisory is shared for download at msrc.microsoft.com. This vulnerability is handled as CVE-2026-78509 since 08/24/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 09/09/2026).

Applying a patch is able to eliminate this problem.

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

Vendor

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License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.5
VulDB Meta Temp Score: 8.4

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 9.8
CNA Vector (microsoft): 🔒

CVSSv2info

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

Exploitinginfo

Class: Heap-based overflow
CWE: CWE-122 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

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

08/24/2026 CVE reserved
09/08/2026 +15 days VulDB entry created
09/09/2026 +0 days Advisory disclosed
09/09/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: microsoft.com

Advisory: msrc.microsoft.com
Status: Confirmed

CVE: CVE-2026-78509 (🔒)
GCVE (CVE): GCVE-0-2026-78509
GCVE (VulDB): GCVE-100-400856

Entryinfo

Created: 09/09/2026 01:15
Changes: 09/09/2026 01:15 (61)
Complete: 🔍
Cache ID: 216::103

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