OpenClaw affected by denial of service via unbounded URL-backed media fetch

Summary

URL-backed media fetch handling allocated the entire response payload in memory (arrayBuffer) before enforcing maxBytes, allowing oversized responses to cause memory exhaustion.

Affected Versions

• openclaw (npm): < 2026.2.14
• clawdbot (npm): <= 2026.1.24-3

Patched Versions

• openclaw (npm): 2026.2.14

Fix Commit

• openclaw/openclaw main: 00a08908892d1743d1fc52e5cbd9499dd5da2fe0

Details

Affected component:

• src/media/input-files.ts (fetchWithGuard)

When content-length is missing or incorrect, reading the body via response.arrayBuffer() buffers the full payload before a size check can run.

Proof of Concept

1. Configure URL-based media input.
2. Serve a response larger than maxBytes (chunked transfer / no content-length).
3. Trigger the fetchWithGuard URL fetch path.

Example local server (large response):

node -e 'require("http").createServer((_,res)=>{res.writeHead(200,{"content-type":"application/octet-stream"});for(let i=0;i<1024;i++)res.write(Buffer.alloc(1024*64));res.end();}).listen(18888)'

Impact

Availability loss via memory pressure from attacker-controlled remote media responses.

Mitigation

Until a patched release is available, disable URL-backed media inputs (or restrict to a tight hostname allowlist) and use conservative maxBytes limits.

Credits

Reported by @vincentkoc.