How severe is CVE-2025-36855?

CVE-2025-36855 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2025-36855 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2025-36855?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2025-36855 have an EU (EUVD) identifier?

Yes. CVE-2025-36855 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-27125.

When was CVE-2025-36855 published?

CVE-2025-36855 was published on 2025-09-08 and last updated on 2026-06-17.

CVE-2025-36855

CVE-2025-36855 is a high-severity vulnerability with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-126.

Key facts

Severity: High (CVSS 3.x base score 8.8)
EPSS exploit prediction: 1% (49th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-27125
Weakness: CWE-126
Published: 2025-09-08
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2025-36855?: 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.
How severe is CVE-2025-36855?: CVE-2025-36855 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-36855 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-36855?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-36855 have an EU (EUVD) identifier?: Yes. CVE-2025-36855 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-27125.
When was CVE-2025-36855 published?: CVE-2025-36855 was published on 2025-09-08 and last updated on 2026-06-17.

References

Other CWE-126 (Buffer Over-read) vulnerabilities

CVE-2026-41898 — Critical (CVSS 9.8): rust-openssl provides OpenSSL bindings for the Rust programming language. From 0.9.24 to before 0.10.78, the FFI…
CVE-2023-36397 — Critical (CVSS 9.8): Windows Pragmatic General Multicast (PGM) Remote Code Execution Vulnerability
CVE-2025-12106 — Critical (CVSS 9.1): Insufficient argument validation in OpenVPN 2.7_alpha1 through 2.7_rc1 allows an attacker to trigger a heap buffer…
CVE-2023-51773 — Critical (CVSS 9.1): BACnet Stack before 1.3.2 has a decode function APDU buffer over-read in bacapp_decode_application_data in bacapp.c.
CVE-2021-34584 — Critical (CVSS 9.1): Crafted web server requests can be utilised to read partial stack or heap memory or may trigger a denial-of- service…
CVE-2025-21176 — High (CVSS 8.8): .NET, .NET Framework, and Visual Studio Remote Code Execution Vulnerability

Browse all CWE-126 (Buffer Over-read) vulnerabilities →