What’s Vulnerable › Vulnerabilities

CVE-2026-108398: .NET Framework Security Feature Bypass Vulnerability

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-13 · updated 2026-10-26
• Weakness: CWE-426

Description

Untrusted search path in .NET Framework allows an authorized attacker to bypass a security feature locally.

Affected products

• Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2: from 3.0.0.0 before 2.0.50727.8987 AND 3.0.30729.8982 AND 4.7.4150.0 — fixed in 2.0.50727.8987 AND 3.0.30729.8982 AND 4.7.4150.0
• Microsoft .NET Framework 3.5 AND 4.7.2: from 4.7.0 before 2.0.50727.9073 AND 3.0.30729.9070 AND 4.7.4150.0 — fixed in 2.0.50727.9073 AND 3.0.30729.9070 AND 4.7.4150.0
• Microsoft .NET Framework 3.5 AND 4.8: from 4.8.0 before 2.0.50727.9073 AND 3.0.30729.9070 AND 4.8.4811.0 — fixed in 2.0.50727.9073 AND 3.0.30729.9070 AND 4.8.4811.0
• Microsoft .NET Framework 3.5 AND 4.8.1: from 4.8.1 before 2.0.50727.9188 AND 3.0.30729.9171 AND 4.8.9363.0 — fixed in 2.0.50727.9188 AND 3.0.30729.9171 AND 4.8.9363.0
• Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2: from 4.7.0 before 4.7.4150.0 — fixed in 4.7.4150.0
• Microsoft .NET Framework 4.8: from 4.8.0 before 4.8.4811.0 — fixed in 4.8.4811.0
• Microsoft .NET Framework 4.8.1: from 4.8.0.0 before 4.8.9363.0 — fixed in 4.8.9363.0

How to fix

Upgrade to a fixed version: Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 2.0.50727.8987 AND 3.0.30729.8982 AND 4.7.4150.0; Microsoft .NET Framework 3.5 AND 4.7.2 2.0.50727.9073 AND 3.0.30729.9070 AND 4.7.4150.0; Microsoft .NET Framework 3.5 AND 4.8 2.0.50727.9073 AND 3.0.30729.9070 AND 4.8.4811.0; Microsoft .NET Framework 3.5 AND 4.8.1 2.0.50727.9188 AND 3.0.30729.9171 AND 4.8.9363.0; Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 4.7.4150.0; Microsoft .NET Framework 4.8 4.8.4811.0; Microsoft .NET Framework 4.8.1 4.8.9363.0. Check the vendor advisory for mitigations.

In the news

• Microsoft’s October 2026 Patch Tuesday addresses 1407 CVEs (CVE-2026-96951)
• Patch Tuesday - October 2026

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-108398

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