F5 NGINX JavaScript up to 1.0.0 js_access authorization

Summaryinfo

A vulnerability has been found in F5 NGINX JavaScript up to 1.0.0 and classified as critical. This affects an unknown part of the component js_access. This manipulation causes authorization. This vulnerability is handled as CVE-2026-18329. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability has been found in F5 NGINX JavaScript up to 1.0.0 and classified as critical. Affected by this vulnerability is an unknown part of the component js_access. The manipulation with an unknown input leads to a authorization vulnerability. The CWE definition for the vulnerability is CWE-639. The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at my.f5.com. This vulnerability is known as CVE-2026-18329 since 07/29/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/02/2026).

Upgrading to version 1.0.1 eliminates this vulnerability.

Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

• Web Server

Vendor

• F5

Name

• NGINX JavaScript

Version

• 1.0

License

• commercial

Website

• Vendor: https://f5.com/

CPE 2.3info

• 🔒

CPE 2.2info

• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Be aware that VulDB is the high quality source for vulnerability data.

Discussion