CVE-2026-42420: OpenClaw before 2026.4.8 contains improper input validation in base64 decode paths that allocate memory before

Routine

MEDIUM 4.3UPGRADE

CVE-2026-42420 is a medium-severity flaw (CVSS 4.3) affecting openclaw. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

OpenClaw before 2026.4.8 contains improper input validation in base64 decode paths that allocate memory before enforcing decoded-size limits. Attackers can exploit multiple code paths to cause memory exhaustion or denial of service through crafted base64-encoded input.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	4.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.3% (top 77%)
CISA exploited list	No
Weakness	CWE-770
Published	2026-04-28
Last modified	2026-06-17

Publisher (CNA): VulnCheck · Vendor: openclaw

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-28 19:37 UTCPublished CVE record published
2026-06-17 10:47 UTCUpdated Record last modified

openclaw openclaw UPGRADE

Affected: < 2026.4.8

Fixed in: 2026.4.8

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls openclaw

2. UPGRADE to 2026.4.8

npm install openclaw@">=2026.4.8"

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-2026-42420?

openclaw: upgrade to 2026.4.8. Exact commands for each OS are on this page.

Is CVE-2026-42420 being exploited?

CVE-2026-42420 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-2026-42420 affect?

CVE-2026-42420 affects openclaw. Severity is medium (CVSS 4.3). OpenClaw before 2026.4.8 contains improper input validation in base64 decode paths that allocate memory before enforcing decoded-size limits. Attackers can exploit multiple code paths to cause memory exhaustion or denial of service through

How urgent is CVE-2026-42420?

Priority 21/100. No elevated risk signals yet.

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References

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