CVE-2026-63308: Helm through 4.2.3, fixed in commit ba6c9a2, contains a denial of service vulnerability in the Files.Lines tem

Q: How do I fix CVE-2026-63308?

helm: upgrade to newer than 4.2.3. Exact commands for each OS are on this page.

Q: Is CVE-2026-63308 being exploited?

CVE-2026-63308 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-63308 affect?

CVE-2026-63308 affects helm. Severity is medium (CVSS 4.3). Helm through 4.2.3, fixed in commit ba6c9a2, contains a denial of service vulnerability in the Files.Lines template helper in pkg/engine/files.go that allows attackers to trigger an index out of range panic by including zero-length byte sli

Q: How urgent is CVE-2026-63308?

Priority 30/100. Public exploit reference

Routine

MEDIUM 4.3UPGRADE

CVE-2026-63308 is a medium-severity flaw (CVSS 4.3) affecting helm. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Helm through 4.2.3, fixed in commit ba6c9a2, contains a denial of service vulnerability in the Files.Lines template helper in pkg/engine/files.go that allows attackers to trigger an index out of range panic by including zero-length byte slices in chart files. Attackers can include empty files in Helm charts to cause deterministic render failures across template, install, upgrade, lint, and SDK Engine.Render operations.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	4.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.5% (top 58%)
CISA exploited list	No
Weakness	CWE-129
Published	2026-07-17
Last modified	2026-07-30

Publisher (CNA): VulnCheck · Vendor: helm

Last updated 2026-07-30 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-17 17:17 UTCPublished CVE record published
2026-07-30 18:11 UTCUpdated Record last modified

helm helm UPGRADE

Affected: <= 4.2.3

Fixed in: newer than 4.2.3

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy helm || rpm -q helm || helm --version

2. UPGRADE to newer than 4.2.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade helm

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade helm

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-63308?

helm: upgrade to newer than 4.2.3. Exact commands for each OS are on this page.

Is CVE-2026-63308 being exploited?

CVE-2026-63308 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-63308 affect?

CVE-2026-63308 affects helm. Severity is medium (CVSS 4.3). Helm through 4.2.3, fixed in commit ba6c9a2, contains a denial of service vulnerability in the Files.Lines template helper in pkg/engine/files.go that allows attackers to trigger an index out of range panic by including zero-length byte sli

How urgent is CVE-2026-63308?

Priority 30/100. Public exploit reference

Software pages

Helm vulnerabilities

References

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