CVE-2020-36187

Q: What is the severity of CVE-2020-36187?

CVE-2020-36187 has a CVSS score of 8.1 (HIGH). This vulnerability in FasterXML jackson-databind allows remote code execution through deserialization of untrusted data. It affects applications using Jackson 2.x with default typing enabled that process external input. Attackers can exploit this to execute arbitrary code on vulnerable systems.

8.1 HIGH

Remote Code Execution Deserialization

📋 TL;DR

This vulnerability in FasterXML jackson-databind allows remote code execution through deserialization of untrusted data. It affects applications using Jackson 2.x with default typing enabled that process external input. Attackers can exploit this to execute arbitrary code on vulnerable systems.

💻 Affected Systems

Products:

FasterXML jackson-databind
Applications using Jackson for JSON processing

Versions: 2.x before 2.9.10.8

Operating Systems: All operating systems running Java applications

Default Config Vulnerable: ✅ No

Notes: Only vulnerable when default typing is enabled (ObjectMapper.enableDefaultTyping() or similar) and processing untrusted data.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution leading to complete system compromise, data theft, and lateral movement within the network.

🟠

Likely Case

Remote code execution resulting in application compromise, data exfiltration, and potential privilege escalation.

🟢

If Mitigated

Limited impact if proper input validation and deserialization controls are implemented, potentially reduced to denial of service.

🌐 Internet-Facing: HIGH - Internet-facing applications processing untrusted JSON data are directly exploitable.

🏢 Internal Only: MEDIUM - Internal applications may still be vulnerable if they process untrusted data from internal sources.

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: LIKELY

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires specific conditions but has been demonstrated in proof-of-concept code.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 2.9.10.8 or later (2.10.x, 2.11.x, 2.12.x)

Vendor Advisory: https://github.com/FasterXML/jackson-databind/issues/2997

Restart Required: Yes

Instructions:

1. Update jackson-databind dependency to version 2.9.10.8 or later. 2. Update pom.xml or build.gradle with new version. 3. Rebuild and redeploy application. 4. Restart affected services.

🔧 Temporary Workarounds

Disable default typing

all

Disable polymorphic type handling in Jackson ObjectMapper configuration

// Java code: objectMapper.disableDefaultTyping();
// Or avoid using enableDefaultTyping() methods

Use safe typing configuration

all

Configure ObjectMapper with explicit safe typing using @JsonTypeInfo annotations

// Use @JsonTypeInfo with explicit type names instead of default typing

🧯 If You Can't Patch

Implement strict input validation and sanitization for all JSON inputs
Use security controls like application firewalls to block malicious payloads

🔍 How to Verify

Check if Vulnerable:

Check Maven/Gradle dependencies for jackson-databind version <2.9.10.8 and verify if default typing is enabled in code.

Check Version:

mvn dependency:tree | grep jackson-databind OR gradle dependencies | grep jackson-databind

Verify Fix Applied:

Verify jackson-databind version is 2.9.10.8 or higher in dependency files and deployed artifacts.

📡 Detection & Monitoring

Log Indicators:

Unusual Java class loading errors
Unexpected deserialization exceptions
Suspicious network connections after JSON processing

Network Indicators:

HTTP requests with crafted JSON payloads containing class names
Outbound connections to unexpected destinations after JSON processing

SIEM Query:

source="application.log" AND ("ClassNotFoundException" OR "NoClassDefFoundError") AND "jackson"

📊 Metadata

CVE ID: CVE-2020-36187

CVSS v3 Score: 8.1 (HIGH)

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE: CWE-502

Published: January 6, 2021

Last Updated: November 21, 2024

🔗 References

https://cowtowncoder.medium.com/on-jackson-cves-dont-panic-here-is-what-you-need-to-know-54cd0d6e8062 Exploit,Technical Description,Third Party Advisory
https://github.com/FasterXML/jackson-databind/issues/2997 Issue Tracking,Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/04/msg00025.html Mailing List,Third Party Advisory
https://security.netapp.com/advisory/ntap-20210205-0005/ Third Party Advisory
https://www.oracle.com//security-alerts/cpujul2021.html Patch,Third Party Advisory
https://www.oracle.com/security-alerts/cpuApr2021.html Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.html Patch,Third Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html Patch,Third Party Advisory
https://www.oracle.com/security-alerts/cpujul2022.html Third Party Advisory
https://www.oracle.com/security-alerts/cpuoct2021.html Patch,Third Party Advisory
https://cowtowncoder.medium.com/on-jackson-cves-dont-panic-here-is-what-you-need-to-know-54cd0d6e8062 Exploit,Technical Description,Third Party Advisory
https://github.com/FasterXML/jackson-databind/issues/2997 Issue Tracking,Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/04/msg00025.html Mailing List,Third Party Advisory
https://security.netapp.com/advisory/ntap-20210205-0005/ Third Party Advisory
https://www.oracle.com//security-alerts/cpujul2021.html Patch,Third Party Advisory
https://www.oracle.com/security-alerts/cpuApr2021.html Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.html Patch,Third Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html Patch,Third Party Advisory
https://www.oracle.com/security-alerts/cpujul2022.html Third Party Advisory
https://www.oracle.com/security-alerts/cpuoct2021.html Patch,Third Party Advisory

📋 TL;DR

💻 Affected Systems

📦 What is this software?

Agile Plm by Oracle

Application Testing Suite by Oracle

Autovue For Agile Product Lifecycle Management by Oracle

Banking Corporate Lending Process Management by Oracle

Banking Corporate Lending Process Management by Oracle

Banking Corporate Lending Process Management by Oracle

Banking Credit Facilities Process Management by Oracle

Banking Credit Facilities Process Management by Oracle

Banking Credit Facilities Process Management by Oracle

Banking Extensibility Workbench by Oracle

Banking Extensibility Workbench by Oracle

Banking Extensibility Workbench by Oracle

Banking Supply Chain Finance by Oracle

Banking Supply Chain Finance by Oracle

Banking Supply Chain Finance by Oracle

Banking Treasury Management by Oracle

Banking Virtual Account Management by Oracle

Banking Virtual Account Management by Oracle

Banking Virtual Account Management by Oracle

Blockchain Platform by Oracle

Cloud Backup by Netapp

Commerce Platform by Oracle

Commerce Platform by Oracle

Communications Billing And Revenue Management by Oracle

Communications Billing And Revenue Management by Oracle

Communications Cloud Native Core Policy by Oracle

Communications Cloud Native Core Unified Data Repository by Oracle

Communications Convergent Charging Controller by Oracle

Communications Diameter Signaling Route by Oracle

Communications Element Manager by Oracle

Communications Evolved Communications Application Server by Oracle

Communications Instant Messaging Server by Oracle

Communications Network Charging And Control by Oracle

Communications Offline Mediation Controller by Oracle

Communications Policy Management by Oracle

Communications Pricing Design Center by Oracle

Communications Services Gatekeeper by Oracle

Communications Session Report Manager by Oracle

Communications Session Route Manager by Oracle

Communications Unified Inventory Management by Oracle

Data Integrator by Oracle

Debian Linux by Debian

Documaker by Oracle

Documaker by Oracle

Documaker by Oracle

Goldengate Application Adapters by Oracle

Insurance Policy Administration by Oracle

Insurance Policy Administration by Oracle

Insurance Rules Palette by Oracle

Insurance Rules Palette by Oracle

Jackson Databind by Fasterxml

Jackson Databind by Fasterxml

Jd Edwards Enterpriseone Orchestrator by Oracle

Jd Edwards Enterpriseone Tools by Oracle

Primavera Gateway by Oracle

Primavera Gateway by Oracle

Primavera Gateway by Oracle

Primavera Gateway by Oracle

Primavera Unifier by Oracle

Primavera Unifier by Oracle

Primavera Unifier by Oracle

Primavera Unifier by Oracle

Primavera Unifier by Oracle

Retail Customer Management And Segmentation Foundation by Oracle

Retail Merchandising System by Oracle

Retail Service Backbone by Oracle

Retail Service Backbone by Oracle

Retail Service Backbone by Oracle

Retail Xstore Point Of Service by Oracle

Retail Xstore Point Of Service by Oracle

Retail Xstore Point Of Service by Oracle

Retail Xstore Point Of Service by Oracle

Service Level Manager by Netapp

Webcenter Portal by Oracle

Webcenter Portal by Oracle

⚠️ Risk & Real-World Impact

Worst Case