UBUNTU-CVE-2026-33186

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Source
https://ubuntu.com/security/CVE-2026-33186
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33186.json
JSON Data
https://api.test.osv.dev/v1/vulns/UBUNTU-CVE-2026-33186
Upstream
Published
2026-03-20T23:16:00Z
Modified
2026-03-25T20:00:19.475181Z
Severity
  • 9.1 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N CVSS Calculator
  • Ubuntu - high
Summary
[none]
Details

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 using canonical paths (starting with /) failed to match the incoming request, allowing it to bypass the policy if a fallback "allow" rule was present. This affects gRPC-Go servers that use path-based authorization interceptors, such as the official RBAC implementation in google.golang.org/grpc/authz or custom interceptors relying on info.FullMethod or grpc.Method(ctx); AND that have a security policy contains specific "deny" rules for canonical paths but allows other requests by default (a fallback "allow" rule). The vulnerability is exploitable by an attacker who can send raw HTTP/2 frames with malformed :path headers directly to the gRPC server. The fix in version 1.79.3 ensures that any request with a :path that does not start with a leading slash is immediately rejected with a codes.Unimplemented error, preventing it from reaching authorization interceptors or handlers with a non-canonical path string. While upgrading is the most secure and recommended path, users can mitigate the vulnerability using one of the following methods: Use a validating interceptor (recommended mitigation); infrastructure-level normalization; and/or policy hardening.

References

Affected packages

Ubuntu:16.04:LTS
golang-google-grpc

Package

Name
golang-google-grpc
Purl
pkg:deb/ubuntu/golang-google-grpc@0.0~git20151002.0.3e7b7e5-1?arch=source&distro=xenial

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.0~git20150514.0.f5ebd86-1
0.0~git20150514.0.f5ebd86-2
0.0~git20151002.0.3e7b7e5-1

Ecosystem specific 

{
    "priority_reason": "bruce> Remote attacker can bypass security policies",
    "binaries": [
        {
            "binary_name": "golang-google-grpc-dev",
            "binary_version": "0.0~git20151002.0.3e7b7e5-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33186.json"
Ubuntu:18.04:LTS
golang-google-grpc

Package

Name
golang-google-grpc
Purl
pkg:deb/ubuntu/golang-google-grpc@1.6.0-3ubuntu0.18.04.1?arch=source&distro=bionic

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.0.4-1
1.6.0-2
1.6.0-3
1.6.0-3ubuntu0.18.04.1

Ecosystem specific 

{
    "priority_reason": "bruce> Remote attacker can bypass security policies",
    "binaries": [
        {
            "binary_name": "golang-google-grpc-dev",
            "binary_version": "1.6.0-3ubuntu0.18.04.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33186.json"
Ubuntu:20.04:LTS
golang-google-grpc

Package

Name
golang-google-grpc
Purl
pkg:deb/ubuntu/golang-google-grpc@1.22.1-1ubuntu1?arch=source&distro=focal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.22.1-1ubuntu1

Ecosystem specific 

{
    "priority_reason": "bruce> Remote attacker can bypass security policies",
    "binaries": [
        {
            "binary_name": "golang-google-grpc-dev",
            "binary_version": "1.22.1-1ubuntu1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33186.json"
Ubuntu:22.04:LTS
golang-google-grpc

Package

Name
golang-google-grpc
Purl
pkg:deb/ubuntu/golang-google-grpc@1.29.1-0ubuntu1?arch=source&distro=jammy

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.29.1-0ubuntu1

Ecosystem specific 

{
    "priority_reason": "bruce> Remote attacker can bypass security policies",
    "binaries": [
        {
            "binary_name": "golang-google-grpc-dev",
            "binary_version": "1.29.1-0ubuntu1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33186.json"
google-guest-agent

Package

Name
google-guest-agent
Purl
pkg:deb/ubuntu/google-guest-agent@20250116.00-0ubuntu1~22.04.2?arch=source&distro=jammy

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

20210629.*
20210629.00-0ubuntu1
20210629.00-0ubuntu2
20220104.*
20220104.00-0ubuntu1
20220104.00-0ubuntu2
20220622.*
20220622.00-0ubuntu2~22.04.0
20220622.00-0ubuntu2~22.04.1
20230426.*
20230426.00-0ubuntu2~22.04.0
20231004.*
20231004.02-0ubuntu1~22.04.1
20231004.02-0ubuntu1~22.04.2
20231004.02-0ubuntu1~22.04.3
20231004.02-0ubuntu1~22.04.4
20231004.02-0ubuntu1~22.04.5
20240716.*
20240716.00-0ubuntu1~22.04.0
20241011.*
20241011.01-0ubuntu1~22.04.0
20250116.*
20250116.00-0ubuntu1~22.04.0
20250116.00-0ubuntu1~22.04.1
20250116.00-0ubuntu1~22.04.2

Ecosystem specific 

{
    "priority_reason": "bruce> Remote attacker can bypass security policies",
    "binaries": [
        {
            "binary_name": "google-guest-agent",
            "binary_version": "20250116.00-0ubuntu1~22.04.2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33186.json"
Ubuntu:24.04:LTS
google-guest-agent

Package

Name
google-guest-agent
Purl
pkg:deb/ubuntu/google-guest-agent@20250116.00-0ubuntu1~24.04.3?arch=source&distro=noble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

20230426.*
20230426.00-0ubuntu3
20231004.*
20231004.02-0ubuntu1
20231004.02-0ubuntu3
20240213.*
20240213.00-0ubuntu1
20240213.00-0ubuntu2
20240213.00-0ubuntu3
20240213.00-0ubuntu3.1
20240213.00-0ubuntu3.2
20240716.*
20240716.00-0ubuntu1~24.04.0
20240716.00-0ubuntu1~24.04.1
20241011.*
20241011.01-0ubuntu1~24.04.0
20250116.*
20250116.00-0ubuntu1~24.04.0
20250116.00-0ubuntu1~24.04.1
20250116.00-0ubuntu1~24.04.2
20250116.00-0ubuntu1~24.04.3

Ecosystem specific 

{
    "priority_reason": "bruce> Remote attacker can bypass security policies",
    "binaries": [
        {
            "binary_name": "google-guest-agent",
            "binary_version": "20250116.00-0ubuntu1~24.04.3"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33186.json"
Ubuntu:25.10
golang-google-grpc

Package

Name
golang-google-grpc
Purl
pkg:deb/ubuntu/golang-google-grpc@1.64.0-7?arch=source&distro=questing

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.64.0-6
1.64.0-7

Ecosystem specific 

{
    "priority_reason": "bruce> Remote attacker can bypass security policies",
    "binaries": [
        {
            "binary_name": "golang-google-grpc-dev",
            "binary_version": "1.64.0-7"
        },
        {
            "binary_name": "protoc-gen-go-grpc",
            "binary_version": "1.64.0-7"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33186.json"
google-guest-agent

Package

Name
google-guest-agent
Purl
pkg:deb/ubuntu/google-guest-agent@20250506.01-0ubuntu1.1?arch=source&distro=questing

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

20250116.*
20250116.00-0ubuntu2
20250506.*
20250506.01-0ubuntu1
20250506.01-0ubuntu1.1

Ecosystem specific 

{
    "priority_reason": "bruce> Remote attacker can bypass security policies",
    "binaries": [
        {
            "binary_name": "google-guest-agent",
            "binary_version": "20250506.01-0ubuntu1.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33186.json"
Ubuntu:Pro:16.04:LTS
google-guest-agent

Package

Name
google-guest-agent
Purl
pkg:deb/ubuntu/google-guest-agent@20240716.00-0ubuntu1~16.04.0+esm2?arch=source&distro=esm-apps/xenial

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

20201217.*
20201217.02-0ubuntu1~16.04.0
20230426.*
20230426.00-0ubuntu2~16.04.3
20231004.*
20231004.02-0ubuntu1~16.04.1
20231004.02-0ubuntu1~16.04.2
20240716.*
20240716.00-0ubuntu1~16.04.0
20240716.00-0ubuntu1~16.04.0+esm1
20240716.00-0ubuntu1~16.04.0+esm2

Ecosystem specific 

{
    "priority_reason": "bruce> Remote attacker can bypass security policies",
    "binaries": [
        {
            "binary_name": "google-guest-agent",
            "binary_version": "20240716.00-0ubuntu1~16.04.0+esm2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33186.json"
Ubuntu:Pro:18.04:LTS
google-guest-agent

Package

Name
google-guest-agent
Purl
pkg:deb/ubuntu/google-guest-agent@20241011.01-0ubuntu1~18.04.0+esm2?arch=source&distro=esm-apps/bionic

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

20201217.*
20201217.02-0ubuntu1~18.04.0
20210414.*
20210414.00-0ubuntu1~18.04.0
20210629.*
20210629.00-0ubuntu1~18.04.1
20220622.*
20220622.00-0ubuntu2~18.04.0
20220622.00-0ubuntu2~18.04.1
20230426.*
20230426.00-0ubuntu2~18.04.0
20231004.*
20231004.02-0ubuntu1~18.04.2
20231004.02-0ubuntu1~18.04.3
20240716.*
20240716.00-0ubuntu1~18.04.0
20241011.*
20241011.01-0ubuntu1~18.04.0
20241011.01-0ubuntu1~18.04.0+esm1
20241011.01-0ubuntu1~18.04.0+esm2

Ecosystem specific 

{
    "priority_reason": "bruce> Remote attacker can bypass security policies",
    "binaries": [
        {
            "binary_name": "google-guest-agent",
            "binary_version": "20241011.01-0ubuntu1~18.04.0+esm2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33186.json"
Ubuntu:Pro:20.04:LTS
google-guest-agent

Package

Name
google-guest-agent
Purl
pkg:deb/ubuntu/google-guest-agent@20250116.00-0ubuntu1~20.04.0+esm2?arch=source&distro=esm-infra/focal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

20201217.*
20201217.02-0ubuntu1~20.04.0
20210414.*
20210414.00-0ubuntu1~20.04.0
20210629.*
20210629.00-0ubuntu1~20.04.0
20220622.*
20220622.00-0ubuntu2~20.04.0
20220622.00-0ubuntu2~20.04.2
20230426.*
20230426.00-0ubuntu2~20.04.0
20231004.*
20231004.02-0ubuntu1~20.04.1
20231004.02-0ubuntu1~20.04.2
20231004.02-0ubuntu1~20.04.3
20231004.02-0ubuntu1~20.04.4
20240716.*
20240716.00-0ubuntu1~20.04.0
20241011.*
20241011.01-0ubuntu1~20.04.1
20250116.*
20250116.00-0ubuntu1~20.04.0
20250116.00-0ubuntu1~20.04.0+esm1
20250116.00-0ubuntu1~20.04.0+esm2

Ecosystem specific 

{
    "priority_reason": "bruce> Remote attacker can bypass security policies",
    "binaries": [
        {
            "binary_name": "google-guest-agent",
            "binary_version": "20250116.00-0ubuntu1~20.04.0+esm2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33186.json"
Ubuntu:Pro:24.04:LTS
golang-google-grpc

Package

Name
golang-google-grpc
Purl
pkg:deb/ubuntu/golang-google-grpc@1.38.0+really1.33.3-1ubuntu0.24.04.3+esm2?arch=source&distro=esm-apps/noble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.38.0+really1.33.3-1build1
1.38.0+really1.33.3-1ubuntu0.24.04.1
1.38.0+really1.33.3-1ubuntu0.24.04.2
1.38.0+really1.33.3-1ubuntu0.24.04.2+esm1
1.38.0+really1.33.3-1ubuntu0.24.04.3
1.38.0+really1.33.3-1ubuntu0.24.04.3+esm1
1.38.0+really1.33.3-1ubuntu0.24.04.3+esm2

Ecosystem specific 

{
    "priority_reason": "bruce> Remote attacker can bypass security policies",
    "binaries": [
        {
            "binary_name": "golang-google-grpc-dev",
            "binary_version": "1.38.0+really1.33.3-1ubuntu0.24.04.3+esm2"
        },
        {
            "binary_name": "protoc-gen-go-grpc",
            "binary_version": "1.38.0+really1.33.3-1ubuntu0.24.04.3+esm2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33186.json"