Which products and versions are affected by CVE-2013-3861?

Affected: .net Framework (Microsoft) versions 2.0-sp2, 3.5, 3.5.1, 3.5-sp1, 4.0, 4.5. The full list is in the CVE brief.

Is CVE-2013-3861 being exploited in the wild?

It is not listed in any known-exploited vulnerabilities catalog.

Is CVE-2013-3861 in the CISA KEV catalog?

No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.

Is there a public exploit for CVE-2013-3861?

No public exploit code is known.

Is there a fix for CVE-2013-3861?

No fixed version is listed yet; check the vendor advisory for mitigations.

How urgently should CVE-2013-3861 be patched?

Brandefense priority: patch immediately, because it is very likely to be exploited soon.

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Vulnerability Intelligence

CVE-2013-3861

High

Microsoft .NET Framework 2.0 SP2, 3.5, 3.5 SP1, 3.5.1, 4, and 4.5 allows remote attackers to cause a denial of service (application crash or hang) via crafted character sequences in JSON data, aka "JSON Parsing Vulnerability."

Published Oct 9, 2013 · Updated Apr 28, 2026

Key Facts

Patch immediately

CVE-2013-3861 is a high-severity vulnerability (CVSS 7.8 v2) affecting .net Framework (Microsoft).
It is not listed in any known-exploited vulnerabilities catalog. No public exploit code is known.
EPSS estimates a 82% probability of exploitation in the next 30 days.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.

CVSS v2

7.8

AV:N/AC:L/Au:N/C:N/I:N/A:C

EPSS (30-day exploit likelihood)

82%

Higher than 99.6% of all scored CVEs

Exploited in the wild

No known

Not in a known-exploited catalog

Public exploit code

None known

Get the full CVE-2013-3861 brief as a PDF

Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.

Description

Affected Products

6 affected entries in total

Product	Affected versions	Fixed in
.net FrameworkMicrosoft	2.0-sp2, 3.5, 3.5.1, 3.5-sp1, 4.0, 4.5	n/a

Timeline

Publicly disclosed
Oct 9, 2013
Last updated
Apr 28, 2026

Weakness Type

CWE-20 Improper Input Validation

References

FAQ

Common Questions.

Microsoft .NET Framework 2.0 SP2, 3.5, 3.5 SP1, 3.5.1, 4, and 4.5 allows remote attackers to cause a denial of service (application crash or hang) via crafted character sequences in JSON data, aka "JSON Parsing Vulnerability."
Affected: .net Framework (Microsoft) versions 2.0-sp2, 3.5, 3.5.1, 3.5-sp1, 4.0, 4.5. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.

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