CVE-2026-42420
OpenClaw: Multiple Code Paths Missing Base64 Pre-Allocation Size Checks
Description
## Impact Multiple Code Paths Missing Base64 Pre-Allocation Size Checks. Several base64 decode paths could allocate before enforcing decoded-size limits. OpenClaw is a user-controlled local assistant. This advisory is scoped to the OpenClaw trust model and does not assume a multi-tenant service boundary. ## Affected Packages / Versions - Package: `openclaw` (npm) - Affected versions: `<=v2026.4.2` - Patched versions: `2026.4.8` ## Fix The issue was fixed on `main` and is available in the patched npm version listed above. The verified fixed tree is commit `d7c3210cd6f5fdfdc1beff4c9541673e814354d5`. ## Verification The fix was re-checked against `main` before publication, including targeted regression tests for the affected security boundary. ## Credits Thanks @zsxsoft and @KeenSecurityLab for reporting.
How to fix CVE-2026-42420
To remediate CVE-2026-42420, upgrade the affected package to a fixed version below.
- —upgrade to 2026.4.8 or later
Is CVE-2026-42420 being exploited?
Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0, < 2026.4.8
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N |
| osv | CVSS 3.1 | MEDIUM4.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L |