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.

Severity (CVSS 3.1)5.9Medium
Exploit odds (30 days)1.1%top 34.6% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

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

EcosystemPackageFixed inAdvisory
Alpine:v3.20helm3.6.0-r0ALPINE-CVE-2021-21303
Alpine:v3.21helm3.6.0-r0ALPINE-CVE-2021-21303
Alpine:v3.22helm3.6.0-r0ALPINE-CVE-2021-21303
Alpine:v3.23helm3.6.0-r0ALPINE-CVE-2021-21303
Alpine:v3.24helm3.6.0-r0ALPINE-CVE-2021-21303
Gohelm.sh/helm/v33.5.2GO-2022-1040
Gohelm.sh/helm/v33.5.2GHSA-c38g-469g-cmgx
Ubuntu:22.04:LTShelmno fix listedUBUNTU-CVE-2021-21303
Ubuntu:24.04:LTShelmno fix listedUBUNTU-CVE-2021-21303
Ubuntu:25.10helmno fix listedUBUNTU-CVE-2021-21303
Ubuntu:26.04:LTShelmno fix listedUBUNTU-CVE-2021-21303
Ubuntu:26.10helmno fix listedUBUNTU-CVE-2021-21303

Affected products (as reported)

VendorProductVersions
helm helm > 3.0, < 3.5.2

Weakness: CWE-74 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:N

References