UBUNTU-CVE-2026-33540

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Source
https://ubuntu.com/security/CVE-2026-33540
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33540.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-33540
Upstream
  • CVE-2026-33540
Published
2026-04-06T15:17:00Z
Modified
2026-04-13T09:32:07Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

Distribution is a toolkit to pack, ship, store, and deliver container content. Prior to 3.1.0, in pull-through cache mode, distribution discovers token auth endpoints by parsing WWW-Authenticate challenges returned by the configured upstream registry. The realm URL from a bearer challenge is used without validating that it matches the upstream registry host. As a result, an attacker-controlled upstream (or an attacker with MitM position to the upstream) can cause distribution to send the configured upstream credentials via basic auth to an attacker-controlled realm URL. This vulnerability is fixed in 3.1.0.

References

Affected packages

Ubuntu:20.04:LTS
docker-registry

Package

Name
docker-registry
Purl
pkg:deb/ubuntu/docker-registry@2.7.1+ds2-7ubuntu0.3?arch=source&distro=focal

Affected ranges

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

Affected versions

2.*
2.6.2~ds1-2
2.7.1~ds1-2
2.7.1~ds1-3
2.7.1~ds1-4
2.7.1+ds2-5
2.7.1+ds2-7
2.7.1+ds2-7ubuntu0.1
2.7.1+ds2-7ubuntu0.2
2.7.1+ds2-7ubuntu0.3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "2.7.1+ds2-7ubuntu0.3",
            "binary_name": "docker-registry"
        },
        {
            "binary_version": "2.7.1+ds2-7ubuntu0.3",
            "binary_name": "golang-github-docker-distribution-dev"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33540.json"
Ubuntu:24.04:LTS
docker-registry

Package

Name
docker-registry
Purl
pkg:deb/ubuntu/docker-registry@2.8.2+ds1-1ubuntu0.24.04.3?arch=source&distro=noble

Affected ranges

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

Affected versions

2.*
2.8.2+ds1-1build1
2.8.2+ds1-1ubuntu0.24.04.1
2.8.2+ds1-1ubuntu0.24.04.2
2.8.2+ds1-1ubuntu0.24.04.3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "2.8.2+ds1-1ubuntu0.24.04.3",
            "binary_name": "docker-registry"
        },
        {
            "binary_version": "2.8.2+ds1-1ubuntu0.24.04.3",
            "binary_name": "golang-github-docker-distribution-dev"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33540.json"
Ubuntu:25.10
docker-registry

Package

Name
docker-registry
Purl
pkg:deb/ubuntu/docker-registry@2.8.3+ds1-2?arch=source&distro=questing

Affected ranges

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

Affected versions

2.*
2.8.3+ds1-2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "2.8.3+ds1-2",
            "binary_name": "docker-registry"
        },
        {
            "binary_version": "2.8.3+ds1-2",
            "binary_name": "golang-github-docker-distribution-dev"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33540.json"
Ubuntu:Pro:16.04:LTS
docker-registry

Package

Name
docker-registry
Purl
pkg:deb/ubuntu/docker-registry@2.3.0~ds1-1ubuntu0.1~esm1?arch=source&distro=esm-apps/xenial

Affected ranges

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

Affected versions

2.*
2.1.1~ds1-4
2.1.1~ds1-4ubuntu1
2.3.0~ds1-1
2.3.0~ds1-1ubuntu0.1~esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "2.3.0~ds1-1ubuntu0.1~esm1",
            "binary_name": "docker-registry"
        },
        {
            "binary_version": "2.3.0~ds1-1ubuntu0.1~esm1",
            "binary_name": "golang-github-docker-distribution-dev"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33540.json"
Ubuntu:Pro:18.04:LTS
docker-registry

Package

Name
docker-registry
Purl
pkg:deb/ubuntu/docker-registry@2.6.2~ds1-1ubuntu0.1~esm1?arch=source&distro=esm-apps/bionic

Affected ranges

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

Affected versions

2.*
2.6.2~ds1-1
2.6.2~ds1-1ubuntu0.1~esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "2.6.2~ds1-1ubuntu0.1~esm1",
            "binary_name": "docker-registry"
        },
        {
            "binary_version": "2.6.2~ds1-1ubuntu0.1~esm1",
            "binary_name": "golang-github-docker-distribution-dev"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33540.json"
Ubuntu:Pro:22.04:LTS
docker-registry

Package

Name
docker-registry
Purl
pkg:deb/ubuntu/docker-registry@2.8.0+ds1-4ubuntu0.1~esm3?arch=source&distro=esm-apps/jammy

Affected ranges

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

Affected versions

2.*
2.7.1+ds2-7build2
2.8.0+ds1-4
2.8.0+ds1-4ubuntu0.1~esm1
2.8.0+ds1-4ubuntu0.1~esm2
2.8.0+ds1-4ubuntu0.1~esm3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "2.8.0+ds1-4ubuntu0.1~esm3",
            "binary_name": "docker-registry"
        },
        {
            "binary_version": "2.8.0+ds1-4ubuntu0.1~esm3",
            "binary_name": "golang-github-docker-distribution-dev"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33540.json"