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GHSA-q447-rj3r-2cgh CVE-2026-28478

OpenClaw affected by denial of service via unbounded webhook request body buffering

High npm
Severity
8.7 / 10
High · CVSS 4.0
Exploit chance (EPSS)
0.51%
Chance of exploitation in the next 30 days. Higher than 43.27% of scored vulnerabilities.
Known exploited
No
Not in CISA's catalog
Weakness
CWE-400 Uncontrolled Resource Consumption
Fix
2026.2.13
Upgrade openclaw to this version or later

Description

Summary

Multiple webhook handlers accepted and buffered request bodies without a strict unified byte/time limit. A remote unauthenticated attacker could send oversized payloads and cause memory pressure, degrading availability.

Details

Affected packages:

  • openclaw (npm): <2026.2.12
  • clawdbot (npm): <=2026.1.24-3

Root cause:

  • Webhook code paths buffered request payloads without consistent maxBytes + timeoutMs enforcement.
  • Some SDK-backed handlers parse request bodies internally and needed stream-level guards.

Attack shape:

  • Send very large JSON payloads or slow/incomplete uploads to webhook endpoints.
  • Observe elevated memory usage and request handler pressure.

Impact

Remote unauthenticated availability impact (DoS) via request body amplification/memory pressure.

Patch details (implemented)

  • Added shared bounded request-body helper in src/infra/http-body.ts.
  • Exported helper in src/plugin-sdk/index.ts for extension reuse.
  • Migrated webhook body readers to shared helper for:
    • LINE
    • Nextcloud Talk
    • Google Chat
    • Zalo
    • BlueBubbles
    • Nostr profile HTTP
    • Voice-call
    • Gateway hooks
  • Added stream guards for SDK handlers that parse request bodies internally:
    • Slack
    • Telegram
    • Feishu
  • Added explicit Express JSON body limit handling for MS Teams webhook path.
  • Standardized failure responses:
    • 413 Payload Too Large
    • 408 Request Timeout

Tests

  • Added regression tests:
    • src/infra/http-body.test.ts
    • src/line/monitor.read-body.test.ts
    • extensions/nextcloud-talk/src/monitor.read-body.test.ts
  • Focused webhook/security test suite passes for patched paths.

Remediation

Upgrade to the first release containing this patch.

Credits

Thanks @vincentkoc for reporting.

Affected versions

npm

PackageVulnerableFixed in
clawdbot
<= 2026.1.24-3
 No fix yet
openclaw
< 2026.2.13
2026.2.13

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

openclaw npm → 2026.2.13

npm
npm install openclaw@2026.2.13
yarn
yarn add openclaw@2026.2.13
pnpm
pnpm add openclaw@2026.2.13

Severity breakdown

CVSS 4.0 8.7

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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

Attack vector
Network
Attack complexity
Low
Attack requirements
None
Privileges required
None
User interaction
None
Confidentiality (vulnerable system)
None
Integrity (vulnerable system)
None
Availability (vulnerable system)
High
Confidentiality (subsequent systems)
None
Integrity (subsequent systems)
None
Availability (subsequent systems)
None
Exploit maturity
Not defined
Scope
X

CVSS 3.1 7.5

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Weakness

CWE-400: Uncontrolled Resource Consumption

The product does not properly control the allocation and maintenance of a limited resource.

How to prevent it
  • Architecture and Design: Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place. The login application should be protected against DoS attacks as much as possible. Limiting the database access, perhaps by caching result sets, can help minimize the resources expended. To further limit the potential for a DoS attack, consider tracking the rate of requests received from users and blocking requests that exceed a defined rate threshold.
  • Architecture and Design: Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed. The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question. The second solution is simply difficult to effectively institute -- and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.
  • Architecture and Design: Ensure that protocols have specific limits of scale placed on them.
  • Implementation: Ensure that all failures in resource allocation place the system into a safe posture.

References

Advisories

Fixes and patches

Packages

Other links

Timeline

  1. Published
  2. Last updated by the source
  3. Latest EPSS score
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