Use After Free Affecting nginx package, versions [1.30.0,1.30.40)[1.31.2,1.31.3)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-UNMANAGED-NGINX-18017825
- published19 Jul 2026
- disclosed15 Jul 2026
- creditUnknown
Introduced: 15 Jul 2026
CVE-2026-56434 (opens in a new tab)How to fix?
Upgrade nginx to version 1.30.40, 1.31.3 or higher.
Overview
Affected versions of this package are vulnerable to Use After Free in the ngx_http_ssi_module process when the Server-Side Includes (SSI), proxy_pass, and proxy_buffering off directives are configured. An attacker can cause a heap buffer over-read in the worker process by controlling responses from an upstream server through a man-in-the-middle (MITM) position, potentially leading to limited memory modification or a restart of the worker process. This is only exploitable if the affected directives are enabled and the attacker can intercept and manipulate upstream server responses.