CVE-2026-42055 (GCVE-0-2026-42055)
Vulnerability from cvelistv5 – Published: 2026-06-17 14:04 – Updated: 2026-06-30 12:08 X_F5
VLAI?
Title
NGINX ngx_http_proxy_v2_module and ngx_http_grpc_module vulnerability
Summary
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.
Severity ?
8.1 (High)
CWE
- CWE-122 - Heap-based Buffer Overflow
Assigner
References
| URL | Tags | ||||
|---|---|---|---|---|---|
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Impacted products
| Vendor | Product | Version | |||||||
|---|---|---|---|---|---|---|---|---|---|
| F5 | NGINX Open Source |
Affected:
1.13.10 , < 1.31.2
(custom)
Affected: 1.30.2 , < 1.30.3 (custom) |
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Credits
"F5 acknowledges Mufeed VH of Winfunc Research, Trung Nguyen (@everping) of CyStack, Feng Xue and XGPT of ThreatBook, Hcamael and 章鱼哥 of aipyapp, and Zhen Yan (AntAISecurityLab) for bringing this issue to our attention and following the highest standards of coordinated disclosure."
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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