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High 7.5Published Apr 14, 2026
CVE-2026-23666.NET Framework Denial of Service Vulnerability
Updated under an hour ago ()
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It affects Microsoft .NET Framework 3.5 and 8 other products. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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Improper input validation in .NET Framework allows an unauthorized attacker to deny service over a network.
- CVSS
- 7.5 HIGH (v3.1, CNA)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
- Weakness (CWE)
- CWE-755, CWE-366
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- microsoft
- NVD analysis
- Modified
- Record last updated
- Oct 15, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Microsoft Microsoft .NET Framework 3.5 microsoft:net_framework_3.5 (from the name) | 3.5.0 builds before 2.0.50727.8982 & 3.0.30729.8976 | CNA record |
Microsoft Microsoft .NET Framework 3.5 AND 4.7.2 microsoft:net_framework_3.5_and_4.7.2 (from the name) | 4.7.0 builds before 2.0.50727.9068 & 3.0.30729.9065 & 4.7.4141.0 | CNA record |
Microsoft Microsoft .NET Framework 3.5 AND 4.8 microsoft:net_framework_3.5_and_4.8 (from the name) | 4.8.0 builds before 2.0.50727.9068 & 3.0.30729.9065 & 4.8.4801.0 | CNA record |
Microsoft Microsoft .NET Framework 3.5 AND 4.8.1 microsoft:net_framework_3.5_and_4.8.1 (from the name) | 4.8.1 builds before 2.0.50727.9181 & 3.0.30729.9165 & 4.8.9332.0 | CNA record |
Microsoft Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 microsoft:net_framework_4.6.2_4.7_4.7.1_4.7.2 (from the name) | from 4.7.0 before 4.8.4801.0 | CNA record |
Microsoft Microsoft .NET Framework 4.8 microsoft:net_framework_4.8 (from the name) | from 4.8.0 before 4.8.4801.0 | CNA record |
Red Hat Red Hat Enterprise Linux 10 redhat:enterprise_linux | 10 | CISA ADP |
Red Hat Red Hat Hardened Images redhat:hummingbird | 1 | CISA ADP |
microsoft .net_framework microsoft:.net_framework | 3.5; 3.5; 4.7.2; 3.5; 4.8; 3.5; 4.8.1; 4.6.2; and 4 more ranges | NVD |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-23666vendor-advisory, patch
- https://access.redhat.com/security/cve/CVE-2026-23666
- https://bugzilla.redhat.com/show_bug.cgi?id=2458271
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-23666.json
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.