Bug 2489866 (CVE-2026-42055) - CVE-2026-42055 nginx: NGINX: Arbitrary code execution or Denial of Service via heap-based buffer overflow with crafted HTTP/2 headers
Summary: CVE-2026-42055 nginx: NGINX: Arbitrary code execution or Denial of Service vi...
Keywords:
Status: NEW
Alias: CVE-2026-42055
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On: 2492053
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-06-17 16:02 UTC by OSIDB Bzimport
Modified: 2026-06-25 12:28 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
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Last Closed:
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Description OSIDB Bzimport 2026-06-17 16:02:04 UTC
NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_proxy_v2_module and ngx_http_grpc_module modules. This vulnerability exists when the proxy_http_version to 2 or grpc_pass directives are 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. A remote, unauthenticated attacker, along with conditions beyond their control, could send large headers while creating an upstream request. This may cause a heap-based 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. 


Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.


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