Is CVE-2026-42055 actively exploited?

No active exploitation of CVE-2026-42055 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-42055 be exploited remotely?

Yes. CVE-2026-42055 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-42055?

CVE-2026-42055 has a CVSS score of 8.1 (HIGH).

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HIGH

CVE-2026-42055

CWE-122Published: June 17, 2026· Updated: Jun 18, 2026

8.1

CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2026-42055 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 8.1.