Bug 2555431

Summary: CVE-2026-15176 nginx: nginx: heap-based buffer overflow in ngx_http_core_module via alias with rewrite referencing $request_filename [fedora-44]
Product: [Fedora] Fedora Reporter: Srikanth Balasubramanian <sbalasub>
Component: nginxAssignee: Felix Kaechele <felix>
Status: NEW --- QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: high Docs Contact:
Priority: high    
Version: 44CC: felix, jorton, luhliari, mikel, pavel.lisy
Target Milestone: ---Keywords: Security, SecurityTracking
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Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["0e18345d-cc76-41be-8384-f4396aa42ee4"]}
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Bug Blocks: 2552352    

Description Srikanth Balasubramanian 2026-10-19 08:33:06 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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.