Is CVE-2026-42420 in the CISA KEV catalog?

No. CVE-2026-42420 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-42420?

CVE-2026-42420 has a CVSS v3 base score of 4.3 (MEDIUM).

What is the EPSS score for CVE-2026-42420?

CVE-2026-42420 has an EPSS score of 0.30% (22th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-42420?

Upgrade openclaw to 2026.4.8 or later.

CVE & CISA-KEV Catalog

CVE-2026-42420

MEDIUM

4.3

CVSS v3

NVD

Description

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.

CWE-770Allocation of Resources Without Limits or Throttling

How to fix

Remediation Available

openclawNVD

Affected:< 2026.4.8Fixed in:2026.4.8CVE-2026-42420derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityLow

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Exploit Intelligence

0.30%probability of exploitation in 30 days

22ndpercentile

Low risk: more likely to be exploited than 22% of all known CVEs.

References

Patch1

github.com

Vendor Advisory1

github.com

Third-Party Advisory1

vulncheck.com

Related Vulnerabilities

Other CWE-770 (Allocation of Resources Without Limits or Throttling) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-50387	High	7.5	100%	-	Fix
CVE-2019-11478	Medium	5.3	95%	-	Fix
CVE-2019-11479	High	7.5	92%	-	Fix
CVE-2024-27316	High	7.5	91%	-	Fix
CVE-2022-30522	High	7.5	90%	-	Fix
CVE-2019-9515	High	7.5	88%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-30.