CVE-2026-23666

.NET Framework Denial of Service Vulnerability

State: Published
Severity: 7.5 High
Published: Apr 14, 2026
Updated: Oct 15, 2026
Reserved: Jan 14, 2026

Description

Improper input validation in .NET Framework allows an unauthorized attacker to deny service over a network.

Scores

CVSS	Score	Vector	Source
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C	microsoft
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	redhat-SADP

Weaknesses

CWE-755 Improper Handling of Exceptional Conditions
CWE-366 Race Condition within a Thread

Affected Products

Product	Versions
Microsoft .NET Framework 3.5Microsoft	3.5.0 to before 2.0.50727.8982 & 3.0.30729.8976Affected
Microsoft .NET Framework 3.5 AND 4.7.2Microsoft	4.7.0 to before 2.0.50727.9068 & 3.0.30729.9065 & 4.7.4141.0Affected
Microsoft .NET Framework 3.5 AND 4.8Microsoft	4.8.0 to before 2.0.50727.9068 & 3.0.30729.9065 & 4.8.4801.0Affected
Microsoft .NET Framework 3.5 AND 4.8.1Microsoft	4.8.1 to before 2.0.50727.9181 & 3.0.30729.9165 & 4.8.9332.0Affected
Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2Microsoft	4.7.0 to before 4.8.4801.0Affected
Microsoft .NET Framework 4.8Microsoft	4.8.0 to before 4.8.4801.0Affected

References

.NET Framework Denial of Service Vulnerabilityvendor-advisorypatch
https://access.redhat.com/security/cve/CVE-2026-23666vdb-entry
RHBZ#2458271issue-tracking
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-23666.json

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