CVE-2026-33540

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Source
https://cve.org/CVERecord?id=CVE-2026-33540
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-33540.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2026-33540
Aliases
Downstream
Related
Published
2026-04-06T14:55:04.812Z
Modified
2026-04-12T04:30:21.966623Z
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
Summary
Distribution affected by pull-through cache credential exfiltration via www-authenticate bearer realm
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.

Database specific 
{
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33540.json",
    "cwe_ids": [
        "CWE-918"
    ],
    "cna_assigner": "GitHub_M"
}
References

Affected packages

Git / github.com/distribution/distribution

Affected ranges

Type
GIT
Repo
https://github.com/distribution/distribution
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
708f8d6b060248fe7192294dd5440320ffc86da0
Database specific 
{
    "source": "AFFECTED_FIELD",
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "3.1.0"
        }
    ]
}

Affected versions

docs-v2.*
docs-v2.4.1-2016-06-28
v2.*
v2.0.0
v2.0.0-alpha.0
v2.0.0-alpha.1
v2.0.0-alpha.2
v2.0.0-alpha.3
v2.0.0-rc.0
v2.0.0-rc.1
v2.0.0-rc.2
v2.0.0-rc.3
v2.0.0-rc.4
v2.1.0
v2.1.0-rc.0
v2.1.1
v2.2.0
v2.2.1
v2.3.0-alpha
v2.3.0-rc.0
v2.3.0-rc.1
v2.3.0-rc.2
v2.4.0-rc.1
v2.5.0-rc.1
v2.6.0-rc.1
v2.7.0
v2.7.0-rc.0
v3.*
v3.0.0
v3.0.0-alpha.1
v3.0.0-beta.1
v3.0.0-rc.1
v3.0.0-rc.2
v3.0.0-rc.3
v3.0.0-rc.4

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-33540.json"