What is CVE-2019-0657?

CVE-2019-0657 is a medium-severity vulnerability in Microsoft .Net Framework 2.0, classified under Improper Input Validation. CVSS score: 5.9/10. Published 2019-03-05.

How severe is CVE-2019-0657?

Medium severity. CVSS v3 base score is 5.9 out of 10.

Improper input validation in Microsoft .Net Framework 2.0

CVE-2019-0657

A vulnerability exists in certain .Net Framework API's and Visual Studio in the way they parse URL's, aka '.NET Framework and Visual Studio Spoofing Vulnerability'.

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

Published 2019-03-05 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.045 (91.4th percentile), scored 2026-10-21.

Low probability of exploitation in the next 30 days, but still tracked. 91st percentile — 91.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.049 · newest: 0.045 · change: -0.004

Affected products

Microsoft .Net Framework 2.0 — versions Service Pack 2 on Windows Server 2008 for Itanium-Based Systems Service Pack 2
Microsoft .Net Framework 3.0 — versions Service Pack 2 on Windows Server 2008 for Itanium-Based Systems Service Pack 2, Service Pack 2 on Windows Server 2008 for 32-bit Systems Service Pack 2, Service Pack 2 on Windows Server 2008 for x64-based Systems Service Pack 2
Microsoft .Net Framework 3.5 — versions Windows Server 2012, Windows Server 2012 (Server Core installation), Windows 8.1 for 32-bit systems
Microsoft .Net Framework 3.5.1 — versions Windows 7 for 32-bit Systems Service Pack 1, Windows 7 for x64-based Systems Service Pack 1, Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
Microsoft .Net Framework 4.5.2 — versions Windows 7 for 32-bit Systems Service Pack 1, Windows 7 for x64-based Systems Service Pack 1, Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
Microsoft .Net Framework 4.6 — versions Windows Server 2008 for 32-bit Systems Service Pack 2, Windows Server 2008 for x64-based Systems Service Pack 2
Microsoft .Net Framework 4.6.2/4.7/4.7.1/4.7.2 — versions Windows Server 2016, Windows 10 Version 1607 for 32-bit Systems, Windows 10 Version 1607 for x64-based Systems
Microsoft .Net Framework 4.6/4.6.1/4.6.2 — versions Windows 10 for 32-bit Systems, Windows 10 for x64-based Systems
Microsoft .Net Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 — versions Windows 7 for 32-bit Systems Service Pack 1, Windows 7 for x64-based Systems Service Pack 1, Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
Microsoft .Net Framework 4.7.1/4.7.2 — versions Windows 10 Version 1709 for 32-bit Systems, Windows 10 Version 1709 for x64-based Systems, Windows Server, version 1709 (Server Core Installation)

Weakness classification (CWE)

CWE-20 — Improper Input Validation

References

access.redhat.com/errata/RHSA-2019:0349 (vendor-advisory, Third Party Advisory)
portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-0657 (Patch, Vendor Advisory)
www.securityfocus.com/bid/106890 (VDB Entry, Third Party Advisory, vdb-entry)

Frequently asked questions

What is CVE-2019-0657?: CVE-2019-0657 is a medium-severity vulnerability in Microsoft .Net Framework 2.0, classified under Improper Input Validation. CVSS score: 5.9/10. Published 2019-03-05.
How severe is CVE-2019-0657?: Medium severity. CVSS v3 base score is 5.9 out of 10.