CVE-2026-29609

OpenClaw versions prior to 2026.2.14 contain a denial of service vulnerability in the fetchWithGuard function that allocates entire response payloads in memory before enforcing maxBytes limits. Remote attackers can trigger memory exhaustion by serving oversized responses without content-length headers to cause availability loss.

OpenClaw versions prior to 2026.2.14 contain a denial of service vulnerability in the fetchWithGuard function that allocates entire response payloads in memory before enforcing maxBytes limits. Remote attackers can trigger memory exhaustion by serving oversized responses without content-length headers to cause availability loss.

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.

OpenClaw versions prior to 2026.2.14 contain a denial of service vulnerability in the fetchWithGuard function that allocates entire response payloads in memory before enforcing maxBytes limits. Remote attackers can trigger memory exhaustion by serving oversized responses without content-length headers to cause availability loss.

OpenClaw versions prior to 2026.2.14 contain a denial of service vulnerability in the fetchWithGuard function that allocates entire response payloads in memory before enforcing maxBytes limits. Remote attackers can trigger memory exhaustion by serving oversized responses without content-length headers to cause availability loss.

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.