Cyber Resilience

CVE-2026-33116

DoS in Microsoft .Net Framework 3.5 … 4.8.1

Published
14 April 2026
Modified
25 July 2026
Patch / advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.021 80th percentile
Risk Priority 66 floored blend · peak EPSS

Summary

CVE-2026-33116 is a high-severity Improper Input Validation (CWE-20) vulnerability in Microsoft .Net Framework. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked in the top 20% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to CM-6 (Configuration Settings) and SA-11 (Developer Testing and Evaluation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-33116 is an infinite loop vulnerability, also described under CWE-835, CWE-400, and CWE-20, that affects .NET, .NET Framework, and Visual Studio. The flaw permits an attacker to trigger a loop with an unreachable exit condition, resulting in a denial-of-service condition. It carries a CVSS 3.1 base score of 7.5 reflecting network attack vector, low complexity, and no required privileges or user interaction, with high impact on availability and no impact on confidentiality or integrity.

An unauthenticated remote attacker can exploit the issue over a network to cause the affected .NET components or Visual Studio instances to become unresponsive, thereby denying service to legitimate users or processes. The attack requires no authentication or user interaction and can be launched solely by sending crafted network traffic that induces the unreachable loop.

Microsoft publishes mitigation guidance and patch information for this vulnerability through its Security Response Center at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-33116. The current EPSS score of 0.0801 with a recorded peak of 0.0918 indicates modest and stable exploitation interest since disclosure.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Loop with unreachable exit condition ('infinite loop') in .NET, .NET Framework, Visual Studio allows an unauthorized attacker to deny service over a network.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
T1499.001 OS Exhaustion Flood Impact
Adversaries may launch a denial of service (DoS) attack targeting an endpoint's operating system (OS).
T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1498 Network Denial of Service Impact
Adversaries may perform Network Denial of Service (DoS) attacks to degrade or block the availability of targeted resources to users.
T1499.002 Service Exhaustion Flood Impact
Adversaries may target the different network services provided by systems to conduct a denial of service (DoS).
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-21230Same product: Microsoft Windows 10 1607
CVE-2026-26171Same product: Apple Macos
CVE-2026-35433Same product: Microsoft .Net
CVE-2026-50653Same product: Microsoft .Net Framework
CVE-2026-42899Same product: Apple Macos
CVE-2026-32203Same product: Apple Macos
CVE-2026-32177Same product: Microsoft .Net
CVE-2025-55692Same product: Microsoft Windows 10 1607
CVE-2026-26170Same product: Microsoft Windows 10 1607
CVE-2026-45642Same product: Microsoft Windows 10 1607

Affected Assets

microsoft
.net
10.0.0 — 10.0.6 · 8.0.0 — 8.0.26 · 9.0.0 — 9.0.15
microsoft
.net framework
3.5, 4.6.2, 4.7, 4.7.1, 4.7.2

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 6 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)

Mitigating Controls (NIST 800-53 r5) AI

Secure configuration settings can disable DTD processing or cap entity expansion in XML parsers.

Developer testing and evaluation can discover missing input validation through analysis or test cases.

SC-5 directly limits the effects of resource-exhaustion events that constitute uncontrolled consumption.

SC-6 enforces explicit allocation limits on resources, structurally preventing the weakness from occurring.

SI-10 directly requires validity checks on information inputs, structurally preventing improper or missing validation.

Flaw remediation processes identify and correct infinite-loop defects reported from testing or operations.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 full match
prevents

Secure SDLC practices directly prevent introduction of improper recursive entity handling in XML code.

PR.IR-04 mostly match
prevents

Explicitly requires monitoring and maintaining resource capacity, directly addressing uncontrolled consumption to preserve availability.

PR.PS-01 mostly match
prevents

Hardened configuration baselines can disable or limit DTD entity expansion in XML parsers.

DE.CM-09 partial match
prevents

Continuous monitoring of computing resources can detect resource exhaustion but does not itself enforce allocation limits.

ID.RA-01 partial match
prevents

Static analysis and vuln scanning during asset assessment can detect unreachable loop exits.

PR.IR-03 partial match
prevents

Resilience mechanisms such as avoiding single points of failure indirectly reduce impact of resource exhaustion.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Resource-utilization monitoring and alerting on bottlenecks or overloads limits the impact of denial-of-service or resource-exhaustion attacks.

finds

Testing against a defined set of requirements and using code review plus vulnerability scanning forces validation of inputs and handling of unanticipated conditions, reducing the chance that malformed data will be accepted.

prevents

By continuously monitoring utilization, stress-testing peak loads, and maintaining documented plans to scale or throttle resources, the control directly limits an attacker’s ability to drive a system into uncontrolled resource exhaustion.

finds

Pre-agreed severity-based prioritization and resource allocation during incident triage reduce the likelihood that an attacker-induced resource exhaustion will overwhelm the organization before corrective action is taken.

mitigates

Business-continuity plans that include resource-management controls reduce the likelihood that an attacker can trigger uncontrolled resource consumption by forcing the system into a degraded or fallback state.

mitigates

Defining RTOs and capacity requirements for ICT services during business-impact analysis forces organizations to provision sufficient resources and throttling mechanisms, reducing the likelihood that an attacker can induce denial-of-service through uncontrolled resource consumption.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

RHEL 8 (1 rule)
  • V-230265 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-20

References