CVE-2021-29441
Published: 27 April 2021
Summary
CVE-2021-29441 is a high-severity Authentication Bypass by Spoofing (CWE-290) vulnerability in Alibaba Nacos. Its CVSS base score is 8.6 (High).
Operationally, ranked in the top 0.1% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
This vulnerability is AI-related — categorised as Other AI Platforms.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-0744
Vulnerability details
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…
more
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.
- CWE(s)
AI Security AnalysisAI
- AI Category
- Other AI Platforms
- Risk Domain
- N/A
- OWASP Top 10 for LLMs 2025
- None mapped
- Classification Reason
- Matched keywords: backdoor
Related Threats
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Reveals spoofed logon attempts through unexpected previous logon timestamps upon legitimate login.
Training specifically addresses recognizing spoofed communications and phishing that enable authentication bypass.
Requiring verifiable identity evidence at appropriate assurance levels makes it substantially harder for attackers to successfully spoof or impersonate users to obtain accounts.
Unique device authentication makes successful spoofing of device identity substantially more difficult to achieve.
Unique identification of non-organizational users reduces the feasibility of authentication bypass by spoofing.
Unique identification and authentication of services before communications makes spoofing of service identities substantially harder.
Isolated trusted path ensures the user interacts only with genuine system components, preventing spoofing of authentication interfaces or prompts.
Directly counters DNS response spoofing by requiring cryptographic origin authentication artifacts from the authoritative source.