CVE-2021-29441highobserved exploitationCWE-290

CVE-2021-29441: high-severity vulnerability in alibaba nacos

Authentication bypass

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100Vexday Risk Score

Patch now. It exploitation observed by VulnCheck and has a working public exploit.

ssvc Actcvss 8.6epss 83%
from disclosure to weapon322 days
Published on NVDApr 27
1st PoC+322d
VulnCheck+948d
In short

Nacos servers can bypass authentication by spoofing a specific user-agent header, allowing attackers to perform administrative tasks without valid credentials. This undermines the entire authentication system when it is enabled.

Technical detail

CWE-290 authentication bypass in AuthFilter servlet filter; the vulnerability allows remote attackers to skip authentication checks by manipulating the user-agent HTTP header. Affected versions before 1.4.1 with authentication enabled (-Dnacos.core.auth.enabled=true) are susceptible, enabling full administrative access without credentials.

Summary generated and translated by AI from the official 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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
Affected products
alibaba · nacos
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