| Title | nanocoai nanoclaw <= 2.1.17 Improper Link Resolution Before File Access / Link Following (CWE-59) |
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| Description | # Technical Details
A symlink-following arbitrary file write vulnerability exists in the `forwardAttachedFiles()` method in `src/modules/agent-to-agent/agent-route.ts` of NanoClaw (npm package `nanoclaw`).
NanoClaw's built-in agent-to-agent (A2A) attachment forwarding trusts the target inbox path. `forwardAttachedFiles()` hardens the source side (rejects unsafe message ids, refuses symlinked source outbox directories and files, resolves `realSrc` and checks containment under the canonical source outbox), but performs no equivalent `lstat()` or `realpath()` containment checks on the target inbox before calling `fs.mkdirSync()` and `fs.copyFileSync()`.
The vulnerable code:
```js
const targetInboxDir = path.join(sessionDir(target.agentGroupId, target.sessionId), 'inbox', target.messageId);
fs.mkdirSync(targetInboxDir, { recursive: true });
...
const dst = path.join(targetInboxDir, filename);
fs.copyFileSync(realSrc, dst); |
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| Source | ⚠️ https://github.com/nanocoai/nanoclaw/issues/2828 |
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| User | Eric-a (UID 96353) |
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| Submission | 08/11/2026 14:52 (1 month ago) |
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| Moderation | 09/13/2026 18:00 (1 month later) |
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| Status | Accepted |
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| VulDB entry | 403309 [nanocoai NanoClaw up to 2.1.17 Attachment agent-route.ts forwardAttachedFiles link following] |
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| Points | 20 |
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