CVE-2021-29441
Authentication bypass
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
Description
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.
Official description from the CVE record, published by GitHub_M. Copyright © 1999-2026 The MITRE Corporation. See /security/cve/legal for the CVE license. View the record on cve.org
Key data
CVSS 3.1 High 8.6
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
Attack vector: Network
The vulnerable component can be reached over a network, possibly from the Internet.
Attack complexity: Low
No special conditions are needed. The attack can be repeated at will.
Privileges required: None
No account or privileges are needed.
User interaction: None
No action from any user is needed.
Scope: Changed
The impact can reach other components beyond the vulnerable one.
Confidentiality impact: High
Serious or total effect on the secrecy of data.
Integrity impact: None
No effect on the trustworthiness of data.
Availability impact: None
No effect on availability.
| Metric | Value | What it means |
|---|---|---|
| Attack vector | Network | The vulnerable component can be reached over a network, possibly from the Internet. |
| Attack complexity | Low | No special conditions are needed. The attack can be repeated at will. |
| Privileges required | None | No account or privileges are needed. |
| User interaction | None | No action from any user is needed. |
| Scope | Changed | The impact can reach other components beyond the vulnerable one. |
| Confidentiality impact | High | Serious or total effect on the secrecy of data. |
| Integrity impact | None | No effect on the trustworthiness of data. |
| Availability impact | None | No effect on availability. |
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EPSS
- Score
- 0.83236 (83.2% probability)
- Percentile
- 99.7%
- Scores of
- Nov 10, 2026
- Model
- v2026.06.15
Weakness (CWE)
- CWE-290Authentication Bypass by Spoofing
Affected products
alibaba nacos
- affected: < 1.4.1
References
Timeline
- ID reserved
- Record published
- Record last updated
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About CubePath
Data from the CVE Program (MITRE), CISA KEV and FIRST EPSS. CVSS is owned by FIRST and used by permission. Not affiliated with or endorsed by MITRE, CISA or FIRST. Data as of Nov 10, 2026, 19:50 UTC. Sources and licenses