CVE-2019-9845: MadsKristensen.AspNetCore.Miniblog MadsKristensen.AspNetCore.Miniblog Subject To Improper Input Vulnerability

CRITICAL
Advisory Identifier: GHSA-958r-g534-ccmr
Share
CVSS 9.8
CWE-20
Published
Advisory Summary

CVE-2019-9845 is a CRITICAL (CVSS 9.8) madskristensen.aspnetcore.miniblog subject to improper input vulnerability (CWE-20: Improper Input Validation) affecting MadsKristensen.AspNetCore.Miniblog libraries in the NuGet ecosystem. The issue involves madskristensen.aspnetcore.miniblog subject to improper input validation. Remediation is available in the latest vendor maintenance releases.

CVE-2019-9845 at a Glance

CVE Identifier CVE-2019-9845
GHSA Identifier GHSA-958r-g534-ccmr
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-20: Improper Input Validation
Affected Product MadsKristensen.AspNetCore.Miniblog
Package Ecosystem NuGet
Published Date
Last Updated

Security Impact

CVSS: 9.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2019-9845

To remediate this vulnerability, upgrade all affected MadsKristensen.AspNetCore.Miniblog dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

MadsKristensen.AspNetCore.Miniblog fixed: Latest secure release 
Upgrade MadsKristensen.AspNetCore.Miniblog to Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for MadsKristensen.AspNetCore.Miniblog

How to Check if You Are Affected

To determine whether your application is affected by CVE-2019-9845, inspect your project dependencies for MadsKristensen.AspNetCore.Miniblog:

inspect dependencies for MadsKristensen.AspNetCore.Miniblog

Analyze the terminal output to locate any version of MadsKristensen.AspNetCore.Miniblog in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-20: Improper Input Validation, where the product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. In MadsKristensen.AspNetCore.Miniblog, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

madskristensen Miniblog.Core through 2019-01-16 allows remote attackers to execute arbitrary ASPX code via an IMG element with a data: URL, because SaveFilesToDisk in Controllers/BlogController.cs writes a decoded base64 string to a file without validating the extension.

CVE-2019-9845 Affected MadsKristensen.AspNetCore.Miniblog Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
MadsKristensen.AspNetCore.Miniblog
nuget/MadsKristensen.AspNetCore.Miniblog
NuGet
≤ 1.0.3

References

NVD — CVE-2019-9845 NVD
https://nvd.nist.gov/vuln/detail/CVE-2019-9845
GitHub Advisory / Wiki ADVISORY
https://github.com/advisories/GHSA-958r-g534-ccmr
MadsKristensen.AspNetCore.Miniblog Source Repository REPOSITORY
https://github.com/madskristensen/Miniblog.Core
MadsKristensen.AspNetCore.Miniblog Source Repository REPOSITORY
https://github.com/madskristensen/Miniblog.Core/blob/master/src/Controllers/BlogController.cs#L142
rastating.github.io/miniblog-remote-cod... WEB
https://rastating.github.io/miniblog-remote-code-execution

Frequently Asked Questions

What is CVE-2019-9845?
CVE-2019-9845 is a security vulnerability in MadsKristensen.AspNetCore.Miniblog involving MadsKristensen.AspNetCore.Miniblog subject to Improper Input Validation under CWE-20: Improper Input Validation.
Which MadsKristensen.AspNetCore.Miniblog versions are affected?
Affected versions include releases prior to current release patches across affected packages: MadsKristensen.AspNetCore.Miniblog.
What version fixes CVE-2019-9845?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is MadsKristensen.AspNetCore.Miniblog affected?
Yes, MadsKristensen.AspNetCore.Miniblog is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2019-9845?
CVE-2019-9845 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2019-9845?
CVE-2019-9845 is classified under CWE-20: Improper Input Validation (The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.).
How can I check NuGet dependencies for CVE-2019-9845?
Run the dependency tree command: 'inspect dependencies for MadsKristensen.AspNetCore.Miniblog'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-958r-g534-ccmr",
  "modified" : "2022-09-17T00:54:46Z",
  "published" : "2019-07-05T21:11:13Z",
  "aliases" : [ "CVE-2019-9845" ],
  "summary" : "MadsKristensen.AspNetCore.Miniblog subject to Improper Input Validation",
  "details" : "madskristensen Miniblog.Core through 2019-01-16 allows remote attackers to execute arbitrary ASPX code via an IMG element with a data: URL, because SaveFilesToDisk in Controllers/BlogController.cs writes a decoded base64 string to a file without validating the extension.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "NuGet",
      "name" : "MadsKristensen.AspNetCore.Miniblog"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "1.0.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2019-9845"
  }, {
    "type" : "ADVISORY",
    "url" : "https://github.com/advisories/GHSA-958r-g534-ccmr"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/madskristensen/Miniblog.Core"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/madskristensen/Miniblog.Core/blob/master/src/Controllers/BlogController.cs#L142"
  }, {
    "type" : "WEB",
    "url" : "https://rastating.github.io/miniblog-remote-code-execution"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-20" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2020-06-16T21:27:35Z",
    "nvd_published_at" : null
  }
}