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A vulnerability ( CVE-2025-21176 https://www.cve.org...

High severity Unreviewed Published Sep 8, 2025 to the GitHub Advisory Database • Updated Sep 8, 2025

Package

No package listed— Suggest a package

Affected versions

Unknown

Patched versions

Unknown

Description

A vulnerability ( CVE-2025-21176 https://www.cve.org/CVERecord ) exists in DiaSymReader.dll due to buffer over-read.

Per CWE-126: Buffer Over-read https://cwe.mitre.org/data/definitions/126.html , Buffer Over-read is when a product reads from a buffer using buffer access mechanisms such as indexes or pointers that reference memory locations after the targeted buffer.

This issue affects EOL ASP.NET 6.0.0 <= 6.0.36 as represented in this CVE, as well as 8.0.0 <= 8.0.11 & <= 9.0.0 as represented in CVE-2025-21176.

Additionally, if you've deployed self-contained applications https://docs.microsoft.com/dotnet/core/deploying/#self-contained-deployments-scd  targeting any of the impacted versions, these applications are also vulnerable and must be recompiled and redeployed.

NOTE: This CVE affects only End Of Life (EOL) software components. The vendor, Microsoft, has indicated there will be no future updates nor support provided upon inquiry.

References

Published by the National Vulnerability Database Sep 8, 2025
Published to the GitHub Advisory Database Sep 8, 2025
Last updated Sep 8, 2025

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(24th percentile)

Weaknesses

Buffer Over-read

The product reads from a buffer using buffer access mechanisms such as indexes or pointers that reference memory locations after the targeted buffer. Learn more on MITRE.

CVE ID

CVE-2025-36855

GHSA ID

GHSA-642h-ggvv-j2c4

Source code

No known source code

Dependabot alerts are not supported on this advisory because it does not have a package from a supported ecosystem with an affected and fixed version.

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