CVE-2026-50659

.NET Spoofing Vulnerability

At a glance

Severity: MEDIUM 6.5
EPSS: EPSS 0.74 % · percentile 54 (2026-10-27)
State: PUBLISHED
Published: 2026-07-14
Updated: 2026-10-08
Assigner: microsoft
NVD status: Analyzed

Description

Improper encoding or escaping of output in .NET allows an authorized attacker to perform spoofing over a network.

Scores

Version	Score	Vector	Scored by
CVSS 3.1	MEDIUM 6.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C	microsoft
CVSS 3.1	MEDIUM 6.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N	NVD · secure@microsoft.com (Secondary)

Weaknesses (CWE)

CWE-116

Advisories

GHSA-74jp-vm22-8q8x — Microsoft Security Advisory CVE-2026-50659 – .NET Spoofing Vulnerability

European references

ENISA EUVD · EUVD-2026-44407
GCVE · GCVE-0-2026-50659

CERT-FR advisories

CERTFR-2026-AVI-0872 — Multiples vulnérabilités dans les produits Microsoft · cert.ssi.gouv.fr
CERTFR-2026-AVI-0870 — Multiples vulnérabilités dans Microsoft .Net · cert.ssi.gouv.fr
CERTFR-2026-AVI-0869 — Multiples vulnérabilités dans Microsoft Windows · cert.ssi.gouv.fr

Affected configurations (NVD CPE)

cpe:2.3:a:microsoft:.net_framework:4.8.1:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:4.8:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:4.6.2:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:4.7:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:4.7.1:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:4.7.2:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net:*:*:*:*:*:*:*:* ≥ 8.0.0 < 8.0.29
cpe:2.3:a:microsoft:.net:*:*:*:*:*:*:*:* ≥ 9.0.0 < 9.0.18
cpe:2.3:a:microsoft:.net:*:*:*:*:*:*:*:* ≥ 10.0.0 < 10.0.6
cpe:2.3:a:microsoft:.net_framework:3.5:-:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:4.8.1:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:3.5:-:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:4.8:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:3.5:-:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:4.7.2:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:.net_framework:3.5:-:*:*:*:*:*:*
cpe:2.3:a:microsoft:visual_studio_2022:*:*:*:*:*:*:*:* ≥ 17.12.0 < 17.12.22
cpe:2.3:a:microsoft:visual_studio_2022:*:*:*:*:*:*:*:* ≥ 17.14.0 < 17.14.36
cpe:2.3:a:microsoft:visual_studio_2026:*:*:*:*:*:*:*:* ≥ 18.7.0 < 18.7.4

Affected products

Product	Versions
Microsoft · .NET 10.0	affected 10.0.0 < 10.0.10
Microsoft · .NET 8.0	affected 8.0.0 < 8.0.29
Microsoft · .NET 9.0	affected 9.0.0 < 9.0.18
Microsoft · Microsoft .NET Framework 3.5	affected 3.5.0 < 2.0.50727.8983 & 3.0.30729.8978
Microsoft · Microsoft .NET Framework 3.5 AND 4.7.2	affected 4.7.0 < 2.0.50727.9069 & 3.0.30729.9067 & 4.7.4143.0
Microsoft · Microsoft .NET Framework 3.5 AND 4.8	affected 4.8.0 < 2.0.50727.9069 & 3.0.30729.9067 & 4.8.4803.0
Microsoft · Microsoft .NET Framework 3.5 AND 4.8.1	affected 4.8.1 < 2.0.50727.9182 & 3.0.30729.9168 & 4.8.9339.0
Microsoft · Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2	affected 4.7.0 < 4.7.4143.0
Microsoft · Microsoft .NET Framework 4.8	affected 4.8.0 < 4.8.4803.0
Microsoft · Microsoft .NET Framework 4.8.1	affected 4.8.0.0 < 4.8.9340.0
Microsoft · Microsoft Visual Studio 2022 version 17.12	affected 17.12.0 < 17.12.22
Microsoft · Microsoft Visual Studio 2022 version 17.14	affected 17.14.0 < 17.14.36
Microsoft · Microsoft Visual Studio 2026 version 18.7	affected 18.0 < 18.7.4

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50659

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)	Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD