CVE-2020-1045

Microsoft ASP.NET Core Security Feature Bypass Vulnerability

Description

A security feature bypass vulnerability exists in the way Microsoft ASP.NET Core parses encoded cookie names. 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. The security update addresses the vulnerability by fixing the way the ASP.NET Core cookie parser handles encoded names.

7.5

CVSS

Severity: High

CVSS 3.1 •

CVSS 2.0 •

EPSS 13.78% Top 10%

Vendor Advisory fedoraproject.org Vendor Advisory fedoraproject.org Vendor Advisory microsoft.com

Affected: Microsoft ASP.NET Core 2.1

Affected: Microsoft ASP.NET Core 3.1

References

Link	Tags
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1045	patch vendor advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5LN2FUVBSVPGK7AU3NMLO3YR6CGONQPB/	vendor advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ASICXQXS4M7MTAF6SGQMCLCA63DLCUT3/	vendor advisory
https://github.com/dotnet/core/blob/main/release-notes/3.1/3.1.8/3.1.8.md#changes-in-318	third party advisory release notes
https://security.snyk.io/vuln/SNYK-RHEL8-DOTNET-1439600	third party advisory
https://access.redhat.com/errata/RHSA-2020:3699	third party advisory

Frequently Asked Questions

What is the severity of CVE-2020-1045?: CVE-2020-1045 has been scored as a high severity vulnerability.
How to fix CVE-2020-1045?: To fix CVE-2020-1045, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2020-1045 being actively exploited in the wild?: It is possible that CVE-2020-1045 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~14% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2020-1045?: CVE-2020-1045 affects Microsoft ASP.NET Core 2.1, Microsoft ASP.NET Core 3.1.

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