CVE-2021-21303

lowpriority · track · 27EPSS 0.011 · 65 %ileDEEUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
1.07% (65th) EPSS
CVSS 3.5 · low
Is it mine?
6 products
Check your exposure
Who says so?
5 sources
cnnvd · enisa_euvd · osv · cert_bund

EPSS · scored 2026-10-27

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.

01

cvss

Technical severity, 0–10. One row per scoring source.

6.8
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 3.5–6.8

v2.03.5lowAV:N/AC:M/Au:S/C:N/I:P/A:Nprimary · NVD / NIST USexploitability 6.8 · impact 2.9
v3.16.8mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:Nprimary · NVD / NIST USexploitability 2.3 · impact 4
v3.15.9mediumCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:Nsecondary · ENISA EU
v3.15.9mediumCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:Nsecondary · security-advisories@github.comexploitability 1.5 · impact 4
v3.16.5mediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:Nsecondary · OSV
v3.16.2mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:N/E:Usecondary · CVSS-BT (t0sche)
02

weaknesses

The CWE weakness classes this flaw belongs to.

03

affected products (6)

Products and version ranges known to be affected.

04

advisories (4)

Vendor and ecosystem advisories describing this.

  • WID-SEC-W-2022-2339IBM DB2: Mehrere SchwachstellenDeutsch2022-12-14csaf · cert_bundDE

    Ein entfernter, anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in IBM DB2 on Cloud Pak for Data and Db2 Warehouse on Cloud Pak for Data ausnutzen, um die Vertraulichkeit, Verfügbarkeit und Integrität zu gefährden.

  • GHSA-c38g-469g-cmgxImproper Neutralization of Special Elements in Output in helm.sh/helm/v32021-06-23ghsa · osvUS

    Since Helm 2 was released, a well-documented aspect of Helm is that the Helm chart's version number MUST follow the SemVer2 specification. In the past, Helm would not permit charts with malformed versions. At some point, a patch was merged that changed this - On a version parse error, the version number was simply passed along as-is. This provided a vector for malicious data to be injected into Helm and potentially used in various ways. 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. 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. ### Patches This issue has been resolved in Helm 3.5.2. While this fix does not constitute a breaking change, as all field formatting is now enforced as documented, it is possible that charts that were mistakenly allowed (but invalid) may no longer be available in search indexes. Specifically, **malformed SemVer versions are no longer supported**. This has always been the documented case, but it is true that malformed versions were allowed. Note that this is the first security release since Helm 2's final deprecation. Helm 2 was not audited for vulnerability to this issue, and should be assumed vulnerable.

  • BIT-helm-2021-21303Injection attack in Helm2024-03-06vendor · osvUS

    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.

  • GO-2022-1040Insufficient sanitization of data files in helm.sh/helm/v32022-10-18vendor · osvUS

    Helm does not sanitize all fields read from repository data files. A maliciously crafted data file may contain strings containing arbitrary data. If printed to a terminal, a malicious string could obscure or alter data on the screen.

05

also known as (6)

Other names and identifiers for this entity.

06

sources

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published 2021-02-05modified 2026-06-17
07

references (11)

External citations — patches, advisories, analysis.

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