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CVE-2026-97801

.NET Framework Tampering Vulnerability

Microsoft Microsoft .NET Framework 3.5
Open in ThreatlineRecord JSON
CVSS
7.5High
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.61%Chance of exploitation activity in the next 30 days, higher than 48% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in2.0.50727.9188 AND 3.0.30729.9171Also 2.0.50727.8987 AND 3.0.30729.8982 AND 4.7.4150.0, 2.0.50727.9073 AND 3.0.30729.9070 AND 4.7.4150.0 and 5 moreCVE List
Published13 Oct 2026Updated 23 Oct 2026CVE List

What fixes it

  • 2.0.50727.9188 AND 3.0.30729.9171Microsoft .NET Framework 3.5CVE List
  • 2.0.50727.8987 AND 3.0.30729.8982 AND 4.7.4150.0Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2CVE List
  • 2.0.50727.9073 AND 3.0.30729.9070 AND 4.7.4150.0Microsoft .NET Framework 3.5 AND 4.7.2CVE List
  • 2.0.50727.9073 AND 3.0.30729.9070 AND 4.8.4811.0Microsoft .NET Framework 3.5 AND 4.8CVE List
  • 2.0.50727.9188 AND 3.0.30729.9171 AND 4.8.9363.0Microsoft .NET Framework 3.5 AND 4.8.1CVE List
  • 4.7.4150.0Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2CVE List
Show all 8 fixed versions
  • 4.8.4811.0Microsoft .NET Framework 4.8CVE List
  • 4.8.9363.0Microsoft .NET Framework 4.8.1CVE List

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Vendor and government advisories 1

Vendors that say their products are affected, and agencies that issued alerts. Check each for the fixed release of the product you run.

Reports 1

1 outlet mention it. Reports are not confirmation; each links to its source.

Description

Improper validation of specified type of input in .NET Framework allows an unauthorized attacker to perform tampering over a network.

Text from CVE List

Affected versions 8

  • Microsoft .NET Framework 3.5affected: 3.5.0 before 2.0.50727.9188 AND 3.0.30729.9171CVE List
  • Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2affected: 3.0.0.0 before 2.0.50727.8987 AND 3.0.30729.8982 AND 4.7.4150.0CVE List
  • Microsoft .NET Framework 3.5 AND 4.7.2affected: 4.7.0 before 2.0.50727.9073 AND 3.0.30729.9070 AND 4.7.4150.0CVE List
  • Microsoft .NET Framework 3.5 AND 4.8affected: 4.8.0 before 2.0.50727.9073 AND 3.0.30729.9070 AND 4.8.4811.0CVE List
  • Microsoft .NET Framework 3.5 AND 4.8.1affected: 4.8.1 before 2.0.50727.9188 AND 3.0.30729.9171 AND 4.8.9363.0CVE List
  • Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2affected: 4.7.0 before 4.7.4150.0CVE List
  • Microsoft .NET Framework 4.8affected: 4.8.0 before 4.8.4811.0CVE List
  • Microsoft .NET Framework 4.8.1affected: 4.8.0.0 before 4.8.9363.0CVE List

References 1