CVE-2026-37236Network attack vector

Access control bypass via arbitrary method override

Published Aug 28, 2026 · Updated Aug 28, 2026

Access control bypass in grpc-gateway 2.28.0 allows remote attackers to evade method-based proxy or WAF rules via a crafted POST request. ServeMux.ServeHTTP accepts X-HTTP-Method-Override on form-encoded POST requests and replaces r.Method with the unrestricted, uppercased header value before selecting a route. Reachability requires path-length fallback to remain enabled; exploitation reaches routes that an upstream method filter was intended to block.

CVSS severityUnavailable
Unscored
EPSS probability0.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Access control bypass in grpc-gateway 2.28.0 allows remote attackers to evade method-based proxy or WAF rules via a crafted POST request. ServeMux.ServeHTTP accepts X-HTTP-Method-Override on form-encoded POST requests and replaces r.Method with the unrestricted, uppercased header value before selecting a route. Reachability requires path-length fallback to remain enabled; exploitation reaches routes that an upstream method filter was intended to block.

The record

CVE
CVE-2026-37236
Published
Aug 28, 2026
Updated
Aug 28, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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