CVE-2021-29441

HIGHNVD 8.68.6—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.6 under NVD CVSS v3. EPSS exploit probability: 74.2%, top 1% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Trending — 3 sources updated this weekElevated
8.6
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • High exploitation likelihood — EPSS 74%
CISA-KEV: Not listedEPSS: 74%CVSS: 8.6Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Nacos is a platform designed for dynamic service discovery and configuration and service management. In Nacos before version 1.4.1, when configured to use authentication (-Dnacos.core.auth.enabled=true) Nacos uses the AuthFilter servlet filter to enforce authentication. This filter has a backdoor that enables Nacos servers to bypass this filter and therefore skip authentication checks. This mechanism relies on the user-agent HTTP header so it can be easily spoofed. This issue may allow any user to carry out any administrative tasks on the Nacos server.

CVSS v3
8.6
EG Score
8.6(medium)
EG Risk
—
EPSS
99.4%
KEV
Not listed

Published

April 27, 2021

Last Modified

November 21, 2024

References (6)

Affected Packages

(1 across 1 ecosystem)
Maven(1)
PackageVulnerable rangeFixed inDependents
com.alibaba.nacos:nacos-common0.1.0 ... 1.4.0-BETA (39 versions)1.4.1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 30× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-22 22:46 UTCEG score recompute▼ 0.40
  2. 2026-07-22 14:06 UTCEPSS rescore
  3. 2026-07-22 14:06 UTCEPSS rescore
  4. 2026-07-21 15:22 UTCEPSS rescore
  5. 2026-07-21 15:22 UTCEPSS rescore
  6. 2026-07-20 17:05 UTCEPSS rescore
  7. 2026-07-19 14:28 UTCEPSS rescore
  8. 2026-07-18 21:29 UTCOSV refresh
  9. 2026-07-15 16:55 UTCEPSS rescore
  10. 2026-07-15 16:55 UTCEPSS rescore
  11. 2026-07-13 06:10 UTCEPSS rescore
  12. 2026-07-11 08:25 UTCEPSS rescore
  13. 2026-07-11 08:25 UTCEPSS rescore
  14. 2026-07-09 19:07 UTCEPSS rescore
  15. 2026-07-05 02:28 UTCEPSS rescore
  16. 2026-07-04 06:29 UTCEPSS rescore
  17. 2026-07-04 06:29 UTCEPSS rescore
  18. 2026-07-01 15:03 UTCEPSS rescore
  19. 2026-07-01 04:18 UTCOSV refresh
  20. 2026-06-30 23:20 UTCEPSS rescore
  21. 2026-06-30 23:20 UTCEPSS rescore
  22. 2026-06-28 14:05 UTCEPSS rescore
  23. 2026-06-28 04:54 UTCEPSS rescore
  24. 2026-06-28 04:54 UTCEPSS rescore
  25. 2026-06-25 13:48 UTCEPSS rescore
Show 26 more
  1. 2026-06-25 13:48 UTCEPSS rescore
  2. 2026-06-24 14:03 UTCEPSS rescore
  3. 2026-06-24 14:03 UTCEPSS rescore
  4. 2026-06-23 21:31 UTCEPSS rescore
  5. 2026-06-23 21:31 UTCEPSS rescore
  6. 2026-06-21 14:55 UTCEPSS rescore
  7. 2026-06-21 14:54 UTCEPSS rescore
  8. 2026-06-21 01:58 UTCEPSS rescore
  9. 2026-06-21 01:58 UTCEPSS rescore
  10. 2026-06-18 17:51 UTCEPSS rescore
  11. 2026-06-18 17:51 UTCEPSS rescore
  12. 2026-06-16 17:51 UTCEPSS rescore
  13. 2026-06-15 17:46 UTCEPSS rescore
  14. 2026-06-13 07:13 UTCOSV refresh
  15. 2026-06-12 23:10 UTCEPSS rescore
  16. 2026-06-11 13:58 UTCEPSS rescore
  17. 2026-06-05 06:09 UTCEPSS rescore
  18. 2026-06-05 06:09 UTCEPSS rescore
  19. 2026-06-01 13:50 UTCEPSS rescore
  20. 2026-06-01 13:50 UTCEPSS rescore
  21. 2026-05-29 13:42 UTCEPSS rescore
  22. 2026-05-27 13:39 UTCEPSS rescore
  23. 2026-05-27 13:39 UTCEPSS rescore
  24. 2026-05-26 17:23 UTCEG score recompute
  25. 2026-05-26 07:17 UTCEPSS rescore
  26. 2026-05-26 07:17 UTCEPSS rescore

Publicly available exploits

(1 reference)

Working exploit code is in the public domain. Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Nucleihttp/cves/2021/CVE-2021-29441.yaml
    First seen Jan 1, 2021

    Nacos <1.4.1 - Authentication Bypass

    Open source ↗

Frequently asked(5)

What is CVE-2021-29441?
CVE-2021-29441 is a high vulnerability published on April 27, 2021. Nacos is a platform designed for dynamic service discovery and configuration and service management. In Nacos before version 1.4.1, when configured to use authentication (-Dnacos.core.auth.enabled=true) Nacos uses the AuthFilter servlet filter to enforce authentication. This filter has a backdoor…
When was CVE-2021-29441 disclosed?
CVE-2021-29441 was first published in the National Vulnerability Database on April 27, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-29441 actively exploited?
CVE-2021-29441 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 99.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-29441?
CVE-2021-29441 has a CVSS v3 base score of 8.6 (NVD).
How do I remediate CVE-2021-29441?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-29441, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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