CVE-2026-78222: NGINX ngx_http_js_module vulnerability

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-02 · updated 2026-09-02
Weakness: CWE-476

Description

A vulnerability exists in NGINX JavaScript where a malformed HTTP response received by ngx.fetch() can crash an NGINX worker when trusted JavaScript reads Response.statusText. Exploitation requires control or influence over the fetched HTTP response. Impact: This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system. 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.

Affected products

F5 NGINX JavaScript: from 0.5.1 before 1.0.1 — fixed in 1.0.1

How to fix

Upgrade to a fixed version: F5 NGINX JavaScript 1.0.1. Check the vendor advisory for mitigations.

References

https://my.f5.com/manage/s/article/K000162603

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