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9.2

NGINX can crash or be hijacked by crafted web requests

CVE-2026-15176 · published 1 day ago
Summary

NGINX Plus and NGINX Open Source may crash or allow code execution when a web request uses certain configuration patterns that involve the $request_filename variable. An attacker can send specially crafted requests to trigger a memory error that restarts the server and, in some cases, run their own code. Apply the latest security updates and avoid using $request_filename in alias, rewrite, set, return, or log directives to protect your system.

What to do
  • Update f5 nginx plus to version 37.1.0.1 or later.
  • Update f5 nginx open source to version 1.31.7 or later.
Affected software
Ecosystem VendorProductAffected versions
– f5 nginx plus < 37.1.0.1
– f5 nginx open source < 1.31.7
Debian:12 debian nginx All versions
Original advisory text
NGINX ngx_http_core_module vulnerability
A vulnerability exists in NGINX Plus and NGINX Open Source when a location is configured that uses the alias directive together with rewrite and a set or return directive referencing the $request_filename variable. Alternatively, the same result could be achieved when the $request_filename variable is used in an access log format directive. An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR.

Impact:
This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or to possibly trigger a code execution. 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.
References
Fix within
Internet-facing 3 days
Internal 60 days
  • Not known to be exploited
  • Can be exploited automatically (estimated)
  • Gives an attacker full control (estimated)
Severity
9.2 Critical
Exploitation
<1% chance of attack within 30 days
Type
CWE-122Heap-based Buffer Overflow
Timeline
Published14 Oct 2026
Updated15 Oct 2026
First seen14 Oct 2026
Sources
CVE-2026-15176 · NVD
CVE-2026-15176 · MITRE
DEBIAN-CVE-2026-15176 · OSV
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