CVE-2026-18329

High

Description

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.

SeverityHigh
CVSS8.2
Exploit probability—
ProductNGINX JavaScript
PublishedSep 2, 2026
First seenSep 2, 2026
Weakness typeCWE-636CWE-636

How to fix

Update
  • F5 NGINX JavaScript1.0.1 or later

Affected products

ProductAffected versionsFixed in
F5 NGINX JavaScript1.0.0 ≤ v < 1.0.1, 0.9.91.0.1

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