CVE-2026-35640: OpenClaw before 2026.3.25 parses JSON request bodies before validating webhook signatures, allowing unauthenti

Routine

MEDIUM 5.3REMOTEUPGRADE

CVE-2026-35640 is a medium-severity flaw (CVSS 5.3) affecting openclaw. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

OpenClaw before 2026.3.25 parses JSON request bodies before validating webhook signatures, allowing unauthenticated attackers to force resource-intensive parsing operations. Remote attackers can send malicious webhook requests to trigger denial of service by exhausting server resources through forced JSON parsing before signature rejection.

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 62%)
CISA exploited list	No
Weakness	CWE-696
Published	2026-04-09
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

2026-04-09 22:16 UTCPublished CVE record published
2026-06-17 10:40 UTCUpdated Record last modified

openclaw openclaw UPGRADE

Affected: < 2026.3.25

Fixed in: 2026.3.25

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls openclaw

2. UPGRADE to 2026.3.25

npm install openclaw@">=2026.3.25"

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-2026-35640?

openclaw: upgrade to 2026.3.25. Exact commands for each OS are on this page.

Is CVE-2026-35640 being exploited?

CVE-2026-35640 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-2026-35640 affect?

CVE-2026-35640 affects openclaw. Severity is medium (CVSS 5.3). OpenClaw before 2026.3.25 parses JSON request bodies before validating webhook signatures, allowing unauthenticated attackers to force resource-intensive parsing operations. Remote attackers can send malicious webhook requests to trigger de

How urgent is CVE-2026-35640?

Priority 33/100. Remotely exploitable, no login, no user action

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References

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