How severe is CVE-2026-35640?

No CVSS score has been assigned to CVE-2026-35640 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-35640?

CVE-2026-35640 affects the following packages: openclaw (npm). Ecosystems affected: npm.

How do I fix CVE-2026-35640?

Update openclaw to 2026.3.28 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-35640 is resolved across your whole dependency graph.

How do I detect CVE-2026-35640 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for openclaw, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-35640 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-35640 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-35640 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-35640?

CVE-2026-35640 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 40th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-35640?

CVE-2026-35640 is classified as CWE-696 (CWE-696). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-35640 published, and has it been updated?

CVE-2026-35640 was published on April 9, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

CVE-2026-35640 — openclaw

Fix: openclaw/openclaw@5e8cb22

CVE-2026-35640 is a CWE-696 vulnerability in openclaw. A fix is available for openclaw — see the affected versions and patch details below.

OpenClaw < 2026.3.25 - Denial of Service via Unauthenticated Webhook Request Parsing

Also known asGHSA-3h52-cx59-c456

Published

Apr 9, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-35640.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk+0.02%

Lower risk than most CVEs40th percentile — riskier than 40% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

133other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

openclawnpm

2.9Mdownloads / week

Description

Summary

Feishu webhook reads and parses unauthenticated request bodies before signature validation

Affected Packages / Versions

Package: openclaw
Affected versions: <= 2026.3.24
First patched version: 2026.3.25
Latest published npm version at verification time: 2026.3.24

Details

Feishu webhook handling previously parsed JSON before signature validation, which let unauthenticated callers force full JSON parsing work before rejection. Commit 5e8cb22176e9235e224be0bc530699261eb60e53 reads the raw request body, validates the signature first, and only then parses JSON.

Verified vulnerable on tag v2026.3.24 and fixed on main by commit 5e8cb22176e9235e224be0bc530699261eb60e53.

Fix Commit(s)

5e8cb22176e9235e224be0bc530699261eb60e53

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`openclaw`	all versions	2026.3.28`npm install openclaw@2026.3.28`

Affected Products

1 product · 1 configurations

Application

openclawopenclaw

< 2026.3.25

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for openclaw, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update openclaw to 2026.3.28 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-35640 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

## Summary Feishu webhook reads and parses unauthenticated request bodies before signature validation ## Affected Packages / Versions - Package: `openclaw` - Affected versions: `<= 2026.3.24` - First patched version: `2026.3.25` - Latest published npm version at verification time: `2026.3.24` ## Details Feishu webhook handling previously parsed JSON before signature validation, which let unauthenticated callers force full JSON parsing work before rejection. Commit `5e8cb22176e9235e224be0bc530699261eb60e53` reads the raw request body, validates the signature first, and only then parses JSO

O3 Security · Impact-Aware SCA

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