Vulnerability · Published Feb 5, 2021 · Assigned by GitHub_M
CVE-2021-21303Injection attack in Helm
Medium 5.9
In plain English
A medium-severity injection in helm from helm. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.1% (higher than 65% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Helm is open-source software which is essentially "The Kubernetes Package Manager". Helm is a tool for managing Charts. Charts are packages of pre-configured Kubernetes resources. In Helm from version 3.0 and before version 3.5.2, there a few cases where data loaded from potentially untrusted sources was not properly sanitized. When a SemVer in the `version` field of a chart is invalid, in some cases Helm allows the string to be used "as is" without sanitizing. Helm fails to properly sanitized some fields present on Helm repository `index.yaml` files. Helm does not properly sanitized some fields in the `plugin.yaml` file for plugins In some cases, Helm does not properly sanitize the fields in the `Chart.yaml` file. By exploiting these attack vectors, core maintainers were able to send deceptive information to a terminal screen running the `helm` command, as well as obscure or alter information on the screen. In some cases, we could send codes that terminals used to execute higher-order logic, like clearing a terminal screen. Further, during evaluation, the Helm maintainers discovered a few other fields that were not properly sanitized when read out of repository index files. This fix remedies all such cases, and once again enforces SemVer2 policies on version fields. All users of the Helm 3 should upgrade to the fixed version 3.5.2 or later. Those who use Helm as a library should verify that they either sanitize this data on their own, or use the proper Helm API calls to sanitize the data.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | helm | 3.6.0-r0 | ALPINE-CVE-2021-21303 |
| Alpine:v3.21 | helm | 3.6.0-r0 | ALPINE-CVE-2021-21303 |
| Alpine:v3.22 | helm | 3.6.0-r0 | ALPINE-CVE-2021-21303 |
| Alpine:v3.23 | helm | 3.6.0-r0 | ALPINE-CVE-2021-21303 |
| Alpine:v3.24 | helm | 3.6.0-r0 | ALPINE-CVE-2021-21303 |
| Go | helm.sh/helm/v3 | 3.5.2 | GO-2022-1040 |
| Go | helm.sh/helm/v3 | 3.5.2 | GHSA-c38g-469g-cmgx |
| Ubuntu:22.04:LTS | helm | no fix listed | UBUNTU-CVE-2021-21303 |
| Ubuntu:24.04:LTS | helm | no fix listed | UBUNTU-CVE-2021-21303 |
| Ubuntu:25.10 | helm | no fix listed | UBUNTU-CVE-2021-21303 |
| Ubuntu:26.04:LTS | helm | no fix listed | UBUNTU-CVE-2021-21303 |
| Ubuntu:26.10 | helm | no fix listed | UBUNTU-CVE-2021-21303 |
Affected products (as reported)
Weakness: CWE-74 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:N
References
- https://github.com/helm/helm/security/advisories/GHSA-c38g-469g-cmgx x_refsource_CONFIRM
- https://github.com/helm/helm/commit/6ce9ba60b73013857e2e7c73d3f86ed70bc1ac9a x_refsource_MISC
- https://github.com/helm/helm/releases/tag/v3.5.2 x_refsource_MISC