CVE-2021-29441 (GCVE-0-2021-29441)

Vulnerability from cvelistv5 – Published: 2021-04-27 20:20 – Updated: 2024-08-03 22:02
VLAI Previdian
Title
Authentication bypass
Summary
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.
Severity
8.6 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
CWE
  • CWE-290 - Authentication Bypass by Spoofing
Assigner
References
Impacted products
Vendor Product Version
alibaba nacos Affected: < 1.4.1
Create a notification for this product.
Previdian
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: e9653b1d-4ab1-4440-bddd-2f47172754ed

Vulnerability ID: CVE-2021-29441

Status: Confirmed

Status Updated: 2025-06-28 02:00 CEST

Exploited: Yes

Timestamps
First Seen: 2025-06-28
Asserted: 2025-06-28
Scope
Notes: Authentication bypass | Affected: Alibaba / nacos | CVSS: 8.6 (HIGH) | EPSS: 0.83483 | Used in malware: unknown | Not yet in CISA KEV: True
Evidence

Type: Public Report

Signal: Successful Exploitation

Confidence: 70%

Source: previdian

Details
Feed Previdian (previdian.com)
Title Authentication bypass
Cve Id CVE-2021-29441
Vendor Alibaba
Ghsa Id GHSA-36HP-JR8H-556F
Product nacos
Added Date 2025-06-28T00:00:00.000Z
Cvss Score 8.6
Epss Score 0.83483
Previous Ids
Cvss Severity HIGH
Virtual Patch False
Cvss Estimated False
Epss Percentile 0.99677
Used In Malware unknown
Vulnerability Id CVE-2021-29441
Ahead Of Cisa Kev None
Not Yet In Cisa Kev True
References
Created: 2026-10-02 09:09 CEST | Updated: 2026-10-02 09:09 CEST
Show details on NVD website
To clipboard 

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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.