CVE-2026-42055
NGINX ngx_http_proxy_v2_module and ngx_http_grpc_module vulnerability
Description
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.
INFO
Published Date :
June 17, 2026, 3:16 p.m.
Last Modified :
July 2, 2026, 8:03 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-42055
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | 9dacffd4-cb11-413f-8451-fbbfd4ddc0ab | ||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | ||||
| CVSS 4.0 | CRITICAL | 9dacffd4-cb11-413f-8451-fbbfd4ddc0ab | ||||
| CVSS 4.0 | CRITICAL | [email protected] |
Solution
- Update NGINX to a fixed version.
- Verify proxy and header configurations.
- Disable ASLR if possible.
Public PoC/Exploit Available at Github
CVE-2026-42055 has a 5 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-42055.
| URL | Resource |
|---|---|
| https://my.f5.com/manage/s/article/K000161584 | Vendor Advisory |
| https://access.redhat.com/errata/RHSA-2026:27197 | Third Party Advisory |
| https://access.redhat.com/security/cve/CVE-2026-42055 | Third Party Advisory |
| https://bugzilla.redhat.com/show_bug.cgi?id=2489866 | Third Party Advisory |
| https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42055.json | Third Party Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-42055 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-42055
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
None
Dockerfile Shell Python
patched version of nginx:1.25-bookworm
Dockerfile Makefile Shell Python
CVE-2026-42055 - Draft
Web Application Firewall for nginx
CMake C Shell C++ HTML PHP Perl Python
WNMP One‑Click Stack | WebDAV · Nginx · PHP · MariaDB · Kernel Tuning
Shell HTML
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-42055 vulnerability anywhere in the article.
-
The Hacker News
F5 Patches Two Critical NGINX Open Source Flaws Enabling Remote Code Execution
Ravie LakshmananJun 18, 2026Vulnerability / Cloud Security F5 has released security updates to address two critical security flaws in NGINX Open Source that could be exploited to achieve code execut ... Read more
The following table lists the changes that have been made to the
CVE-2026-42055 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jul. 02, 2026
Action Type Old Value New Value Added CWE CWE-787 Added CPE Configuration OR *cpe:2.3:a:f5:nginx_plus:r30:-:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r31:p1:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r30:p2:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r31:-:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r32:-:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r30:p1:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r32:p1:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r32:p2:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r33:-:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r33:p1:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r33:p2:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r34:-:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r34:p1:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r32:p3:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r33:p3:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r34:p2:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r35:-:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r36:-:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r36:p1:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r35:p1:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r36:p2:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r32:p4:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_app_protect_dos:*:*:*:*:*:*:*:* versions from (including) 4.3.0 up to (including) 4.7.0 *cpe:2.3:a:f5:nginx_gateway_fabric:*:*:*:*:*:*:*:* versions from (including) 1.3.0 up to (including) 1.6.2 *cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:*:*:*:* versions from (including) 3.5.0 up to (including) 3.7.2 *cpe:2.3:a:f5:dos:4.9.0:*:*:*:*:nginx:*:* *cpe:2.3:a:f5:nginx_instance_manager:*:*:*:*:*:*:*:* versions from (including) 2.17.0 up to (including) 2.22.0 *cpe:2.3:a:f5:nginx_plus:*:*:*:*:*:*:*:* versions from (including) 37.0.0 up to (including) 37.0.1 *cpe:2.3:a:f5:waf:*:*:*:*:*:nginx:*:* versions from (including) 5.9.0 up to (including) 5.13.1 *cpe:2.3:a:f5:nginx_gateway_fabric:*:*:*:*:*:*:*:* versions from (including) 2.0.0 up to (excluding) 2.6.4 *cpe:2.3:a:f5:nginx_ingress_controller:*:*:*:*:*:*:*:* versions from (including) 5.0.0 up to (excluding) 5.5.1 *cpe:2.3:a:f5:nginx_ingress_controller:4.0.0:*:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_ingress_controller:4.0.1:*:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_app_protect_waf:*:*:*:*:*:*:*:* versions from (including) 4.10.0 up to (including) 4.16.0 *cpe:2.3:a:f5:nginx_app_protect_waf:*:*:*:*:*:*:*:* versions from (including) 5.2.0 up to (including) 5.8.0 *cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:* versions from (including) 1.30.0 up to (excluding) 1.30.3 *cpe:2.3:a:f5:nginx_open_source:1.31.1:*:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r3:*:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r31:p2:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r31:p3:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r36:p3:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r36:p4:*:*:*:*:*:* *cpe:2.3:a:f5:nginx_plus:r36:p5:*:*:*:*:*:* *cpe:2.3:a:f5:waf:4.8.1:*:*:*:*:nginx:*:* Added Reference Type F5 Networks: https://my.f5.com/manage/s/article/K000161584 Types: Vendor Advisory Added Reference Type redhat-SADP: https://access.redhat.com/errata/RHSA-2026:27197 Types: Third Party Advisory Added Reference Type redhat-SADP: https://access.redhat.com/security/cve/CVE-2026-42055 Types: Third Party Advisory Added Reference Type redhat-SADP: https://bugzilla.redhat.com/show_bug.cgi?id=2489866 Types: Third Party Advisory Added Reference Type redhat-SADP: https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42055.json Types: Third Party Advisory -
CVE Modified by 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Jun. 30, 2026
Action Type Old Value New Value Added Affected [{'cpes': ['cpe:/a:redhat:hummingbird:1'], 'vendor': 'Red Hat', 'product': 'Red Hat Hardened Images', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:10'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 10', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 8', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:9'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 9', 'defaultStatus': 'affected'}] Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-131 Added Reference https://access.redhat.com/errata/RHSA-2026:27197 Added Reference https://access.redhat.com/security/cve/CVE-2026-42055 Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2489866 Added Reference https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42055.json -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 18, 2026
Action Type Old Value New Value Changed SSVC {'id': 'CVE-2026-42055', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-06-17T15:43:07.643763Z'} {'id': 'CVE-2026-42055', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-06-17T00:00:00+00:00'} -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-42055', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-06-17T15:43:07.643763Z'} -
New CVE Received by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'F5', 'modules': ['ngx_http_proxy_v2_module', 'ngx_http_grpc_module'], 'product': 'NGINX Open Source', 'versions': [{'status': 'affected', 'version': '1.13.10', 'lessThan': '1.31.2', 'versionType': 'custom'}, {'status': 'affected', 'version': '1.30.2', 'lessThan': '1.30.3', 'versionType': 'custom'}], 'defaultStatus': 'unknown'}, {'vendor': 'F5', 'modules': ['ngx_http_proxy_v2_module', 'ngx_http_grpc_module'], 'product': 'NGINX Plus', 'versions': [{'status': 'affected', 'version': '37.0', 'lessThan': '37.0.2.1', 'versionType': 'custom'}, {'status': 'affected', 'version': 'R36', 'lessThan': 'R36 P6', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}] Added Description 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. Added CVSS V4.0 AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-122 Added Reference https://my.f5.com/manage/s/article/K000161584