CVE-2026-33116Network attack vector

Application hangs via EncryptedXml infinite loop

Published Apr 14, 2026 · Updated Apr 14, 2026

Improper input validation in Microsoft .NET and .NET Framework allows remote attackers to hang applications through EncryptedXml processing. The EncryptedXml class enters an infinite loop while processing attacker-controlled XML, consuming execution resources indefinitely. Microsoft identifies the class but has not published the affected method or malformed XML structure; no privileges or user interaction are required.

CVSS severity7.5
High
EPSS probability2.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Microsoft .NET and .NET Framework allows remote attackers to hang applications through EncryptedXml processing. The EncryptedXml class enters an infinite loop while processing attacker-controlled XML, consuming execution resources indefinitely. Microsoft identifies the class but has not published the affected method or malformed XML structure; no privileges or user interaction are required.

The record

CVE
CVE-2026-33116
Published
Apr 14, 2026
Updated
Apr 14, 2026
Vendor
Microsoft
Product
Microsoft .NET Framework 3.5 and 4.8
Classifications
CWE-400, CWE-20, CWE-835, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.8.0 <2.0.50727.9068 & 3.0.30729.9065 & 4.8.4801.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft .NET Framework 3.5 and 4.8version=4.8.0 <2.0.50727.9068 & 3.0.30729.9065 & 4.8.4801.0
Microsoft · .NET 9.0version=9.0.0 <9.0.15
Microsoft · .NET 10.0version=10.0.0 <10.0.6
Microsoft · .NET 8version=8.0.0 <8.0.26; version=8.0 <8.0.26
Microsoft · Microsoft .NET Frameworkversion=4.7.0 <2.0.50727.9068 & 3.0.30729.9065 & 4.7.4141.0; version=4.7.0 <4.8.4801.0; version=4.8.1 <2.0.50727.9181 & 3.0.30729.9165 & 4.8.9332.0
Microsoft · Microsoft .NET Framework 3.5version=3.5.0 <2.0.50727.8982 & 3.0.30729.8976
Microsoft · Microsoft .NET Framework 4.8version=4.8.0 <4.8.4801.0

Published CVSS scores

7.5Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
CWE-20Improper Input Validation
CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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