Bug 2527583 (CVE-2026-18329)

Summary: CVE-2026-18329 nginx: NGINX: Authentication bypass via js_access handler failure
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: high    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in NGINX. When the NGINX JavaScript (njs) or QuickJS (qjs) engines process asynchronous request bodies, an exception during access-control evaluation can cause the `js_access` phase to fail open before an explicit denial is returned. An unauthenticated remote attacker can exploit this by sending a crafted HTTP request that triggers an error in the access validation logic. This allows the request to proceed, bypassing authentication or authorization controls and granting unauthorized access to protected resources.
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Description OSIDB Bzimport 2026-09-02 15:59:28 UTC 
Description

NGINX JavaScript (njs) and QuickJS (qjs) engines have a vulnerability when a js_access handler performs asynchronous request body processing and an exception is thrown during asynchronous access-control evaluation before an explicit access denial is returned. An unauthenticated attacker can exploit this vulnerability by sending a crafted HTTP request that triggers an error condition in the access validation logic. This may cause the js_access phase to fail open, allowing the request to proceed instead of being denied, resulting in an authentication or authorization bypass and unauthorized access to protected resources.

Impact

This vulnerability may allow remote attackers to bypass js_access controls. There is no control plane exposure; this is a data plane issue only.




Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.