CVE-2026-50659: .NET Spoofing Vulnerability

11

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.7% (30-day exploitation probability)+8
Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.74%

ahead of 53% of scored CVEs · Oct 14, 2026

Affects

Microsoft

.net and 16 more

CVSS base

6.5

Medium · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

No

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented patch — msrc.microsoft.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Microsoft .net, Microsoft .NET 10.0, Microsoft .NET 8.0…).
Apply the fixed version or the patch documented under Remediation.
Search available logs for exploit probes matching the vulnerability class (input validation), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Microsoft	.net	≥ 10.0.0 and < 10.0.6≥ 9.0.0 and < 9.0.18≥ 8.0.0 and < 8.0.29	Vulnerable	NIST National Vulnerability Database
Microsoft	.NET 10.0	≥ 10.0.0 and < 10.0.10	Vulnerable	CVE Program (cve.org) e CISA ADP
Microsoft	.NET 8.0	≥ 8.0.0 and < 8.0.29	Vulnerable	CVE Program (cve.org) e CISA ADP
Microsoft	.NET 9.0	≥ 9.0.0 and < 9.0.18	Vulnerable	CVE Program (cve.org) e CISA ADP
Microsoft	.net Framework	version 4.8version 3.5version 4.7.2version 4.7.1version 4.8.1version 4.7version 4.6.2	Vulnerable	NIST National Vulnerability Database
Microsoft	Microsoft .NET Framework 3.5	≥ 3.5.0 and < 2.0.50727.8983 & 3.0.30729.8978	Vulnerable	CVE Program (cve.org) e CISA ADP
Microsoft	Microsoft .NET Framework 3.5 AND 4.7.2	≥ 4.7.0 and < 2.0.50727.9069 & 3.0.30729.9067 & 4.7.4143.0	Vulnerable	CVE Program (cve.org) e CISA ADP
Microsoft	Microsoft .NET Framework 3.5 AND 4.8	≥ 4.8.0 and < 2.0.50727.9069 & 3.0.30729.9067 & 4.8.4803.0	Vulnerable	CVE Program (cve.org) e CISA ADP
Microsoft	Microsoft .NET Framework 3.5 AND 4.8.1	≥ 4.8.1 and < 2.0.50727.9182 & 3.0.30729.9168 & 4.8.9339.0	Vulnerable	CVE Program (cve.org) e CISA ADP
Microsoft	Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2	≥ 4.7.0 and < 4.7.4143.0	Vulnerable	CVE Program (cve.org) e CISA ADP
Microsoft	Microsoft .NET Framework 4.8	≥ 4.8.0 and < 4.8.4803.0	Vulnerable	CVE Program (cve.org) e CISA ADP
Microsoft	Microsoft .NET Framework 4.8.1	≥ 4.8.0.0 and < 4.8.9340.0	Vulnerable	CVE Program (cve.org) e CISA ADP
Microsoft	Microsoft Visual Studio 2022 version 17.12	≥ 17.12.0 and < 17.12.22	Vulnerable	CVE Program (cve.org) e CISA ADP
Microsoft	Microsoft Visual Studio 2022 version 17.14	≥ 17.14.0 and < 17.14.36	Vulnerable	CVE Program (cve.org) e CISA ADP
Microsoft	Microsoft Visual Studio 2026 version 18.7	≥ 18.0 and < 18.7.4	Vulnerable	CVE Program (cve.org) e CISA ADP
Microsoft	Visual Studio 2022	≥ 17.14.0 and < 17.14.36≥ 17.12.0 and < 17.12.22	Vulnerable	NIST National Vulnerability Database
Microsoft	Visual Studio 2026	≥ 18.7.0 and < 18.7.4	Vulnerable	NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

Low

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
6.5	CVSS 3.1	Medium	2.8	3.6	secure@microsoft.com via NIST National Vulnerability Database
6.5	CVSS 3.1	Medium	—	—	microsoft via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N (score shown at the top: secure@microsoft.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-116 · Improper Encoding or Escaping of Output

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).

web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

2026
Affected products added · microsoft/.net 10.0, microsoft/.net 8.0, microsoft/.net 9.0, microsoft/microsoft .net framework 3.5, microsoft/microsoft
Oct 14, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 14, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 14, 2026
Fix documented
Oct 14, 2026 · NIST National Vulnerability Database
CVSS changed · 6.5
Oct 14, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 14, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 14, 2026 · NIST National Vulnerability Database
CVE published
Jul 14, 2026 · microsoft

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 14, 2026 – Oct 14, 2026

References

1 on the record

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50659
Patch, Vendor Advisory, vendor-advisory, patch, NIST National Vulnerability Database

Elsewhere on this site

Microsoft
every CVE for this vendor

Input validation
same class

CWE-116
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-109468 ASP.NET Core Denial of Service Vulnerability 2h
High CVE-2026-97801 .NET Framework Tampering Vulnerability 2d
High CVE-2026-97788 Active Directory Federation Services (AD FS) Information Disclosure Vulnerability 2d
High CVE-2026-96958 .NET Denial of Service Vulnerability 2d
High CVE-2026-96960 .NET Denial of Service Vulnerability 2d
High CVE-2026-96959 .NET Denial of Service Vulnerability 2d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-50659 is ".NET Spoofing Vulnerability", rated Medium. It affects .net (Microsoft); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.5 describes technical severity. EPSS 0.74% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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