LiveActive security incident?Get immediate response
CVE Record

CVE-2026-26171: .NET Denial of Service Vulnerability

Uncontrolled resource consumption in .NET allows an unauthorized attacker to deny service over a network.

HighCVSS 7.5Not KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2026-26171 is a high-severity denial-of-service issue in Microsoft .NET and related PowerShell versions. An unauthenticated attacker on the network could trigger excessive resource use and disrupt availability. The provided sources indicate vendor patches exist, but do not describe public exploitation.

Executive priority

Prioritize remediation in the current patch cycle, faster for externally reachable or critical services. The business risk is service disruption, not data theft, based on the supplied sources.

Technical view

The issue is uncontrolled resource consumption affecting .NET 8.0, 9.0, 10.0 and PowerShell 7.5 and 7.6 as listed in the bundle. CVSS 3.1 is 7.5 with network attack vector, low complexity, no privileges, no user interaction, and high availability impact.

Likely exposure

Organizations are exposed where affected .NET or PowerShell versions are deployed, especially in network-reachable services or systems processing untrusted input. Red Hat advisories indicate downstream package relevance for Red Hat environments.

Exploitation context

The bundle marks KEV as false and gives no cited evidence of active exploitation. Treat this as a patch-priority availability risk, not as a confirmed exploited vulnerability based on the provided evidence.

Researcher notes

The source bundle does not provide vulnerable code paths, proof-of-concept details, fixed version numbers, or exploit telemetry. CWE-400, CWE-611, and CWE-776 suggest resource exhaustion patterns, but validation should remain version and advisory based.

Mitigation direction

  • Apply Microsoft guidance and patches for affected .NET and PowerShell versions.
  • Apply relevant Red Hat errata where using Red Hat-packaged .NET components.
  • Prioritize internet-facing and business-critical .NET services for remediation.
  • Limit network exposure for affected services until patched.
  • Monitor vendor advisories for fixed-version and platform-specific guidance.

Validation and detection

  • Inventory deployed .NET and PowerShell versions across hosts, containers, and build images.
  • Map installed packages against MSRC and Red Hat advisory applicability.
  • Confirm patched runtime packages are active after maintenance windows.
  • Check production monitoring for resource exhaustion or availability anomalies.
  • Document exceptions where vendor guidance is pending or not applicable.
Prepared
Confidence
medium
Sources
8

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-400: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cwe · low confidence lookup

CWE-611: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cwe · low confidence lookup

CWE-776: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-26171 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
5Timeline events
2ADP providers
22Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical Impact: partial

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C3.93.6microsoft
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6redhat-SADP

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2026-26171Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Reported to Red Hat.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Made public.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPdotnet: .NET: Security Bypass and Denial of Service Vulnerability
other:Red Hat severity ratingcvssV3_1
  • 2026-04-13T05:00:07.414Z: Reported to Red Hat.
  • 2026-04-14T18:39:18.599Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Microsoft.NET 10.010.0.0Listed
Microsoft.NET 8.08.0.0Listed
Microsoft.NET 9.09.0.0Listed
MicrosoftPowerShell 7.57.5.0Listed
MicrosoftPowerShell 7.67.6.0Listed
Weakness

CWE details

CWE-400CWE-611CWE-776

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.