CVE-2026-27576: OpenClaw Local Stdio Bridge Vulnerability Leading to Reduced Responsiveness
Summary
CVE-2026-27576: Vulnerability The ACP bridge accepted very large prompt text blocks and could assemble oversized prompt payloads before forwarding them to chat.send. Affects openclaw versions < 2026.2.19. Fixed in 2026.2.19. How to fix ↓
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Background
OpenClaw is an open-source package designed for integrating advanced chat functionalities into applications, particularly through local ACP (Application Control Protocol) clients such as IDE integrations. It facilitates communication between applications and chat models, allowing for seamless interactions. However, it has been identified that the package lacks adequate checks for prompt sizes, making it susceptible to performance issues when handling large inputs.
Vulnerability Detail
The vulnerability arises from the ACP bridge's acceptance of excessively large prompt text blocks, which can lead to oversized prompt payloads being forwarded to the chat.send function. This primarily impacts local ACP clients that may send unusually large inputs, resulting in decreased responsiveness during local sessions. While there is no direct remote attack path or privilege escalation risk, the performance degradation and unexpected model usage/cost are significant concerns.
How To Fix
Latest published version: 2026.10.6 as of 22 Oct 2026
npm install openclaw@2026.10.6Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
2026.2.19
This is the first release that contains the fix.
npm install openclaw@2026.2.19Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, users can limit the size of the input prompts manually to ensure they do not exceed 2 MiB, thereby avoiding performance issues until the package is updated.
Conclusion
In summary, the OpenClaw package has a vulnerability (CVE-2026-27576) that affects its local stdio bridge, leading to performance issues with large inputs. Users are advised to update to the patched version and implement size checks to mitigate the impact of this vulnerability.
See every vulnerability recorded for openclaw →
FAQ
The CVSS score of this vulnerability is 4.8, indicating a moderate severity level.
You can use Vulert, which monitors and alerts in real-time for open-source vulnerabilities. By utilizing the Vulert playground, you can check if your application is affected without any signup.
The primary impacts include reduced responsiveness in local ACP sessions and larger-than-expected model usage/cost when oversized prompts are processed.
No, there is no risk of privilege escalation or direct remote attack path in the default ACP model.
The affected components include src/acp/event-mapper.ts and src/acp/translator.ts.
References
Related vulnerabilities
Recent vulnerabilities recorded for openclaw.
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