CVE-2021-36778: Github.com/rancher/rancher Remote Code Execution Vulnerability
HIGHCVE-2021-36778 is a HIGH (CVSS 8.3) remote code execution vulnerability (CWE-522: Insufficiently Protected Credentials) affecting Github.com/rancher/rancher libraries in the Go ecosystem. The issue involves exposure of repository credentials to external third-party sources in rancher. Remediation is available by upgrading affected packages to version 2.6.3, 2.5.12.
CVE-2021-36778 at a Glance
Security Impact
CVSS: 8.3
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L).
How to Fix CVE-2021-36778
To remediate this vulnerability, upgrade all affected Github.com/rancher/rancher dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade github.com/rancher/rancher to 2.6.3
Upgrade github.com/rancher/rancher to 2.5.12
Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for github.com/rancher/rancher
How to Check if You Are Affected
To determine whether your application is affected by CVE-2021-36778, inspect your project dependencies for Github.com/rancher/rancher:
inspect dependencies for github.com/rancher/rancher
Analyze the terminal output to locate any version of Github.com/rancher/rancher in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.6.3), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-522: Insufficiently Protected Credentials, where the product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval. In Github.com/rancher/rancher, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2021-36778 Affected Github.com/rancher/rancher Versions
2 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
github.com/rancher/rancher
|
Go |
≥ 2.6.0
< 2.6.3
|
2.6.3
|
|
github.com/rancher/rancher
|
Go |
≥ 2.5.0
< 2.5.12
|
2.5.12
|
References
Frequently Asked Questions
What is CVE-2021-36778?
Which Github.com/rancher/rancher versions are affected?
What version fixes CVE-2021-36778?
Is github.com/rancher/rancher affected?
What is the CVSS score of CVE-2021-36778?
What CWE is associated with CVE-2021-36778?
How can I check Go dependencies for CVE-2021-36778?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-4fc7-hc63-7fjg",
"modified" : "2022-05-02T19:33:34Z",
"published" : "2022-05-02T19:33:34Z",
"aliases" : [ "CVE-2021-36778" ],
"summary" : "Exposure of repository credentials to external third-party sources in Rancher",
"details" : "### Impact\nThis issue only happens when the user configures access credentials to a private repository in Rancher inside `Apps & Marketplace > Repositories`. It affects Rancher versions 2.5.0 up to and including 2.5.11 and from 2.6.0 up to and including 2.6.2.\n\nAn insufficient check of the same-origin policy when downloading Helm charts from a configured private repository can lead to exposure of the repository credentials to a third-party provider. This exposure happens when the private repository:\n\n1. Does an HTTP redirect to a third-party repository or external storage provider.\n2. Downloads an icon resource for the chart hosted on a third-party provider.\n\nThe address of the private repository is not leaked, only the credentials are leaked in the HTTP `Authorization` header in base64 format.\n\nWith the patched versions, the default behavior now is to only send the private repository credentials when subdomain or domain hostname match when following the redirect or downloading external resources.\n\n### Patches\nPatched versions include releases 2.5.12, 2.6.3 and later versions.\n\n### Workarounds\n1. Update Rancher to a patched version.\n2. Check the Helm charts in your configured private repository for possible redirects to third-party storage, and for Helm chart icons from third-party sources.\n3. Evaluate any Helm chart that might lead to the mentioned scenario and change affected credentials if deemed necessary.\n\n### References\nInformation about the same-origin check and how to disable it is available in Rancher [documentation](https://rancher.com/docs/rancher/v2.6/en/helm-charts/#repositories).\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Reach out to [SUSE Rancher Security team](https://github.com/rancher/rancher/security/policy) for security related inquiries.\n* Open an issue in [Rancher](https://github.com/rancher/rancher/issues/new/choose) repository.\n* Verify our [support matrix](https://www.suse.com/suse-rancher/support-matrix/all-supported-versions/) and [product support lifecycle](https://www.suse.com/lifecycle/).",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/rancher/rancher"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "2.6.0"
}, {
"fixed" : "2.6.3"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/rancher/rancher"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "2.5.0"
}, {
"fixed" : "2.5.12"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/rancher/rancher/security/advisories/GHSA-4fc7-hc63-7fjg"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-36778"
}, {
"type" : "WEB",
"url" : "https://bugzilla.suse.com/show_bug.cgi?id=1191466"
}, {
"type" : "PACKAGE",
"url" : "github.com/rancher/rancher"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-200", "CWE-522", "CWE-863" ],
"severity" : "HIGH",
"github_reviewed" : true,
"github_reviewed_at" : "2022-05-02T19:33:34Z",
"nvd_published_at" : "2022-05-02T12:16:00Z"
}
}