CVE-2025-36855: Microsoft .NET 6.0 · Buffer Over-read
Affects Microsoft .NET 6.0Source CVE Database V5
Mentioned vulnerabilities
Not known to be exploited · CVSS 8.8 High · end of life, no fix coming : replace or isolate Microsoft .NET 6.0; no fix will be released.
Data as of 25 Oct 2026, 19:02 UTC
- EPSS
- 0.7% chance of exploitation in 30 days – higher than 55% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- None coming – the product is end of life
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 8 Sep 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.
What to do
No fix will be released: Microsoft .NET 6.0 is end of life. Replace it, or isolate it from untrusted networks until you can.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Microsoft .NET 6.0 | Affected
| Fixed in– |
AI-suggested
Given the absence of official patches, European organizations should prioritize upgrading to supported .NET versions (e.g., .NET 7 or later) that do not contain this vulnerability. For self-contained applications, recompilation with updated runtimes is essential. Where immediate upgrade is not feasible, organizations should implement strict network segmentation and application whitelisting to limit exposure. Employ runtime application self-protection (RASP) and enhanced monitoring to detect anomalous memory access patterns or crashes indicative of exploitation attempts. Educate users to recognize and avoid phishing or social engineering tactics that could trigger the required user interaction. Additionally, conduct thorough code reviews and security testing of applications using DiaSymReader.dll to identify and mitigate potential exploitation vectors. Finally, maintain robust incident response plans tailored to memory corruption vulnerabilities to quickly contain and remediate any incidents.
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.