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Vulnerability record · public intelligence
CVE-2026-42055
CRITICAL

NGINX ngx_http_proxy_v2_module and ngx_http_grpc_module vulnerability

Published Jun 17, 2026 · Updated Nov 3, 2026

Severity · CVSSCRITICAL · Not scored
Known exploitationNot listed
EPSS / likelihood6.54%
QFinch risk scoreNot available

Original summary

Normalized public record · Updated Nov 3, 2026

NGINX ngx_http_proxy_v2_module and ngx_http_grpc_module vulnerability

Publisher and source text is retained separately from QFinch interpretation.

QFinch assessment

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.

Evidence: public source records

Affected products

Affected scope reported by the available public evidence
Affected package, product or rangeFix status
Consult the referenced vendor advisory for affected versions.Consult source advisory

Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.

Remediation

Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.

  1. Confirm the affected product and reachable code path exist in your environment.
  2. Apply the vendor-supported patch or mitigation from the primary advisory.
  3. Rescan the exact deployed revision and retain verification evidence.
Review primary references

Evidence coverage

FIRST-EPSSCVE-LIST-V5
SSVC priority
MEDIUM
Confidence
Not available
Aliases
None reported

Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.

Sources and record history

  1. my.f5.com ↗
  2. access.redhat.com ↗
  3. access.redhat.com ↗
  4. access.redhat.com ↗
  5. access.redhat.com ↗
  6. access.redhat.com ↗
  7. access.redhat.com ↗
  8. access.redhat.com ↗
  9. access.redhat.com ↗
  10. access.redhat.com ↗
  11. access.redhat.com ↗
  12. bugzilla.redhat.com ↗

Record history

Published Jun 17, 2026 · Last refreshed Nov 3, 2026