Heap-based Buffer Overflow Affecting nginx package, versions [1.30.0,1.30.3)[1.31.1,1.31.2)
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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- published28 Jun 2026
- disclosed17 Jun 2026
- creditUnknown
Introduced: 17 Jun 2026
CVE-2026-42055 (opens in a new tab)How to fix?
Upgrade nginx to version 1.30.3, 1.31.2 or higher.
Overview
Affected versions of this package are vulnerable to Heap-based Buffer Overflow in the ngx_http_proxy_v2_module and ngx_http_grpc_module modules when the proxy_http_version is set to 2 or grpc_pass is used to proxy HTTP/2 traffic, the ignore_invalid_headers directive is set to off, and the large_client_header_buffers directive size is larger than 2 megabytes. An attacker can cause a heap-based buffer overflow in the worker process, potentially leading to a process restart or remote code execution by sending large headers in an upstream request. This is only exploitable if Address Space Layout Randomization (ASLR) is disabled or the attacker can bypass ASLR.