How severe is CVE-2026-35640?

CVE-2026-35640 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.

Is CVE-2026-35640 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-35640?

CVE-2026-35640 affects Openclaw. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-35640?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-35640 have an EU (EUVD) identifier?

Yes. CVE-2026-35640 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-21136.

When was CVE-2026-35640 published?

CVE-2026-35640 was published on 2026-04-09 and last updated on 2026-06-17.

CVE-2026-35640

CVE-2026-35640 is a medium-severity vulnerability in Openclaw with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-696.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v4: 6.9
EPSS exploit prediction: 0% (35th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-21136
Weakness: CWE-696
Affected product: Openclaw
Published: 2026-04-09
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2026-35640?: 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.
How severe is CVE-2026-35640?: CVE-2026-35640 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.
Is CVE-2026-35640 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-35640?: CVE-2026-35640 affects Openclaw. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-35640?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-35640 have an EU (EUVD) identifier?: Yes. CVE-2026-35640 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-21136.
When was CVE-2026-35640 published?: CVE-2026-35640 was published on 2026-04-09 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:openclaw:openclaw:*:*:*:*:*:node.js:*:*

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