CVE-2026-16723: Fastjson Remote Code Execution Vulnerability

CRITICAL
Advisory Identifier: GHSA-crf3-v9rr-v7hj
Share
CVSS 9.0
CWE-20
Published
Advisory Summary

CVE-2026-16723 is a CRITICAL (CVSS 9.0) remote code execution vulnerability (CWE-20: Improper Input Validation) affecting Fastjson libraries in the Maven ecosystem. The issue involves fastjson has a remote code execution (rce) vulnerability. Remediation is available in the latest vendor maintenance releases.

CVE-2026-16723 at a Glance

CVE Identifier CVE-2026-16723
GHSA Identifier GHSA-crf3-v9rr-v7hj
Severity CRITICAL
CVSS v3.1 Base Score 9.0
CWE Classification CWE-20: Improper Input Validation
Affected Product Fastjson
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 9.0

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H).

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

How to Fix CVE-2026-16723

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

com.alibaba:fastjson fixed: Latest secure release 
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>Latest secure release</version>
</dependency>
Verify Direct and Transitive Dependencies

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

mvn dependency:tree -Dincludes=com.alibaba

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-16723, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=com.alibaba

Analyze the terminal output to locate any version of Fastjson 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: The mvn dependency:tree -Dincludes=com.alibaba command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

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 Fastjson, 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

A remote code execution (RCE) vulnerability exists in fastjson 1.2.68 through 1.2.83. This vulnerability is exploitable under fastjson's stock default configuration — no AutoType enablement required, no classpath gadget required.

CVE-2026-16723 Affected Fastjson Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
com.alibaba:fastjson
maven/com.alibaba/fastjson
Maven
≥ 1.2.68
≤ 1.2.83

References

NVD — CVE-2026-16723 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-16723
Fastjson Source Repository REPOSITORY
https://github.com/alibaba/fastjson2
GitHub Advisory / Wiki ADVISORY
https://github.com/alibaba/fastjson2/wiki/Security-Advisory:-Remote-Code-Execution-in-fastjson-1.2.68%E2%80%931.2.83

Frequently Asked Questions

What is CVE-2026-16723?
CVE-2026-16723 is a security vulnerability in Fastjson involving fastjson has a remote code execution (RCE) vulnerability under CWE-20: Improper Input Validation.
Which Fastjson versions are affected?
Affected versions include releases prior to current release patches across affected packages: com.alibaba:fastjson.
What version fixes CVE-2026-16723?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is fastjson affected?
Yes, com.alibaba:fastjson 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-2026-16723?
CVE-2026-16723 has a CVSS v3.1 base score of 9.0 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H.
What CWE is associated with CVE-2026-16723?
CVE-2026-16723 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 Maven dependencies for CVE-2026-16723?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=com.alibaba'. 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-crf3-v9rr-v7hj",
  "modified" : "2026-08-07T18:18:20Z",
  "published" : "2026-07-23T09:32:01Z",
  "aliases" : [ "CVE-2026-16723" ],
  "summary" : "fastjson has a remote code execution (RCE) vulnerability",
  "details" : "A remote code execution (RCE) vulnerability exists in fastjson 1.2.68 through 1.2.83. This vulnerability is exploitable under fastjson's stock default configuration — no AutoType enablement required, no classpath gadget required.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "com.alibaba:fastjson"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.2.68"
      }, {
        "last_affected" : "1.2.83"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-16723"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/alibaba/fastjson2"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/alibaba/fastjson2/wiki/Security-Advisory:-Remote-Code-Execution-in-fastjson-1.2.68%E2%80%931.2.83"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-20" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-08-07T18:18:20Z",
    "nvd_published_at" : "2026-07-23T09:16:26Z"
  }
}