Incorrect Calculation of Buffer Size Affecting nginx package, versions [1.30.0,1.30.40)[1.31.2,1.31.3)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
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-18017824
- published19 Jul 2026
- disclosed15 Jul 2026
- creditUnknown
Introduced: 15 Jul 2026
CVE-2026-42533 (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 Incorrect Calculation of Buffer Size in the map process when regex matching is used and regex capture variables are referenced before the map output variable. An attacker can cause a heap buffer overflow by sending specially crafted HTTP requests. This may result in denial of service due to worker process restarts, and, if Address Space Layout Randomization (ASLR) is disabled or bypassed, may allow arbitrary code execution.