Description
<p>A security feature bypass vulnerability exists in the way Microsoft ASP.NET Core parses encoded cookie names.</p>
<p>The ASP.NET Core cookie parser decodes entire cookie strings which could allow a malicious attacker to set a second cookie with the name being percent encoded.</p>
<p>The security update addresses the vulnerability by fixing the way the ASP.NET Core cookie parser handles encoded names.</p>
Published: 2020-09-11
Score: 7.5 High
EPSS: 20.4% Moderate
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-hxrm-9w7p-39cc Cookie parsing failure
History

Mon, 23 Feb 2026 18:15:00 +0000

Type Values Removed Values Added
Description <p>A security feature bypass vulnerability exists in the way Microsoft ASP.NET Core parses encoded cookie names.</p> <p>The ASP.NET Core cookie parser decodes entire cookie strings which could allow a malicious attacker to set a second cookie with the name being percent encoded.</p> <p>The security update addresses the vulnerability by fixing the way the ASP.NET Core cookie parser handles encoded names.</p> <p>A security feature bypass vulnerability exists in the way Microsoft ASP.NET Core parses encoded cookie names.</p> <p>The ASP.NET Core cookie parser decodes entire cookie strings which could allow a malicious attacker to set a second cookie with the name being percent encoded.</p> <p>The security update addresses the vulnerability by fixing the way the ASP.NET Core cookie parser handles encoded names.</p>

Mon, 18 Nov 2024 17:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Subscriptions

Fedoraproject Fedora
Microsoft Asp.net Core
Redhat Enterprise Linux Enterprise Linux Aus Enterprise Linux Eus Enterprise Linux Tus Rhel Dotnet
cve-icon MITRE

Status: PUBLISHED

Assigner: microsoft

Published:

Updated: 2024-11-18T16:25:38.621Z

Reserved: 2019-11-04T00:00:00.000Z

Link: CVE-2020-1045

cve-icon Vulnrichment

Updated: 2024-08-04T06:25:01.041Z

cve-icon NVD

Status : Modified

Published: 2020-09-11T17:15:18.307

Modified: 2026-02-23T18:23:07.950

Link: CVE-2020-1045

cve-icon Redhat

Severity : Important

Publid Date: 2020-07-01T00:00:00Z

Links: CVE-2020-1045 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses