CVE-2026-35640 json
OpenClaw < 2026.3.25 - Denial of Service via Unauthenticated Webhook Request Parsing
published 7mo ago modified 4mo ago also GHSA-3h52-cx59-c456 , EUVD-2026-21136
- cvss
- 5.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 39%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
Is CVE-2026-35640 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 6mo ago
Exploit prediction
0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 6.9 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N |
| CNA | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
| CNA | 4.0 | 6.9 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| NVD | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | openclaw | <2026.3.28 |
2026.3.28 |
Affected products
- OpenClaw OpenClaw
Classification
References
-
github.com
/openclaw/openclaw/commit/5e8cb22176e9235e224be0bc530699261eb60e53
patch, web
-
github.com
/openclaw/openclaw/security/advisories/GHSA-3h52-cx59-c456
vendor-advisory, web
-
vulncheck.com
/advisories/openclaw-denial-of-service-via-unauthenticated-webhook-request-parsing
third-party-advisory, web
-
nvd.nist.gov
/vuln/detail/CVE-2026-35640
advisory
-
github.com
/openclaw/openclaw
package
Sources
- CVE List CVE-2026-35640
- GitHub Advisory GHSA-3h52-cx59-c456
- NVD CVE-2026-35640
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.