How severe is CVE-2021-43116?

CVE-2021-43116 has a CVSS score of 8.8/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-43116?

CVE-2021-43116 affects the following packages: com.alibaba.nacos:nacos-client (Maven). Ecosystems affected: Maven.

How do I fix CVE-2021-43116?

The records we use list no patched version of com.alibaba.nacos:nacos-client for CVE-2021-43116. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.

How do I detect CVE-2021-43116 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.alibaba.nacos:nacos-client, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-43116 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is CVE-2021-43116 actively exploited in the wild?

Yes. There are 3 known exploit references for CVE-2021-43116, including 1 documented proof-of-concept exploit on Exploit-DB and 2 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2021-43116?

CVE-2021-43116 has an EPSS (Exploit Prediction Scoring System) score of 7.5%, placing it in the 94th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-43116?

CVE-2021-43116 is classified as Improper Authentication (CWE-287). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2021-43116 published, and has it been updated?

CVE-2021-43116 was published on July 5, 2022 and was last updated on October 20, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

HIGH severity

CVE-2021-43116 — nacos-client

HIGH

CVE-2021-43116 is a high-severity (CVSS 8.8) Improper Authentication vulnerability in com.alibaba.nacos:nacos-client. 3 public exploit or proof-of-concept references are indexed, so weaponization risk is real. The records list no fixed version yet; check the vendor advisory below and apply the mitigations in the meantime.

Use of Hard-coded Credentials in Nacos

Also known asGHSA-2g86-r6w2-wqqr

Published

Jul 5, 2022

Updated

Oct 20, 2026

Affected

1 pkg

Patched

See advisory

Exploits

3 known

Exploitation data as of Nov 1, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

7.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs94th percentile — riskier than 94% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

☕com.alibaba.nacos:nacos-client

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

An Access Control vulnerability exists in Nacos 2.0.3 in the access prompt page; enter username and password, click on login to capture packets and then change the returned package, which lets a malicious user login.

Affected Packages

1 total

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`com.alibaba.nacos:nacos-client`	all versions	No fix

Affected Products

1 product · 1 configurations

Application

nacosalibaba

≤ 2.0.3

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

EDB-51205webappsjava

Nacos 2.0.3 - Access Control vulnerability

by Jenson Zhao · Apr 3, 2023

Exploit-DB Source

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for com.alibaba.nacos:nacos-client, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
The records we use list no patched version of com.alibaba.nacos:nacos-client for CVE-2021-43116. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.
Mitigate without a patch
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2021-43116 in your dependencies?

Find it across Maven, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

8.8/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Raw vector

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

CWE Classification

CWE-287Improper Authentication

Weaponization

No Nuclei template or Metasploit module yet. 3 public proof-of-concept references are listed on this page.

OpenSSF Scorecard

Package health score

nacos

5.9/10

Code-Review6/10

Maintained10/10

Branch-ProtectionN/A

Assessed Oct 26, 2026

Timeline

Disclosed

Jul 5, 2022

First exploit

Apr 3, 2023

Last updated

Oct 20, 2026

Identifiers

CVE-2021-43116

GHSA-2g86-r6w2-wqqr

References

Advisorynvd.nist.gov · CVE 2021 43116 Reportgithub.com Reportgithub.com Webpacketstormsecurity.com · Nacos 2.0.3 Access Control Packagegithub.com · nacos

Related vulnerabilities

This CVE is high severity; 6 of 8 other CVEs with CWE-287 are rated as high or higher (top: critical).

CVE-2026-62264GHSA-jf75-q64q-g65rCVE-2026-49272CVE-2026-114616CVE-2026-114607CVE-2026-114618GHSA-r4xp-prcw-77qfCVE-2026-73054Browse all CWE-287

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 20, 2026

CVE-2021-43116 — nacos-client

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Remediation status

Mitigate without a patch

Frequently Asked Questions

Is CVE-2021-43116 in your dependencies?