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Review reviewCritical

CVE-2026-33186

grpc grpc-go, Cryostat 4 on RHEL 9, Red Hat Enterprise Linux 10

gRPC-Go is the Go language implementation of gRPC. Versions prior to 1.79.3 have an authorization bypass resulting from improper input validation of the HTTP/2 `:path` pseudo-header. The gRPC-Go server was too lenient in its routing logic, accepting requests where the `:path` omitted the mandatory leading slash (e.g., `Service/Method` instead of `/Service/Method`). While the server successfully routed these requests to the correct handler, authorization interceptors (including the official `grpc/authz` package) evaluated the raw, non-canonical path string. Consequently, "deny" rules defined...

CVSS
9.1
EPSS
1.56%
72.7% percentile
CISA KEV
Not listed
Published
2026.03.21
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability1.56%
Technical severityCVSS 9.1

Vulnerability overview

gRPC-Go is the Go language implementation of gRPC. Versions prior to 1.79.3 have an authorization bypass resulting from improper input validation of the HTTP/2 `:path` pseudo-header. The gRPC-Go server was too lenient in its routing logic, accepting requests where the `:path` omitted the mandatory leading slash (e.g., `Service/Method` instead of `/Service/Method`). While the server successfully routed these requests to the correct handler, authorization interceptors (including the official `grpc/authz` package) evaluated the raw, non-canonical path string. Consequently, "deny" rules defined...

Affected product and versions

Product
grpc grpc-go, Cryostat 4 on RHEL 9, Red Hat Enterprise Linux 10
Affected versions
>= < 1.79.3, < 1.79.3
Fixed versions
1.79.3

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that grpc grpc-go, Cryostat 4 on RHEL 9, Red Hat Enterprise Linux 10 and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CWE
CWE-285, CWE-551
CVE-2026-33186 — grpc grpc-go, Cryostat 4 on RHEL 9, Red Hat Enterprise Linux 10 | SECUFOCUS NOW