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[webhooks] Fix signature verification bugs #12

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[webhooks] Fix signature verification bugs #12

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48169bd
fix(webhooks): harden signature verification and fix docs
Wydady13 Jun 12, 2026
1cbfc19
fix(webhooks): use order-independent signature header parsing
Wydady13 Jun 12, 2026
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13 changes: 11 additions & 2 deletions webhooks/overview.mdx
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Original file line number Diff line number Diff line change
Expand Up @@ -45,14 +45,23 @@ Every v1 webhook request includes an `x-topgg-signature` header in the format `t
import crypto from 'crypto';

function verifyWebhook(rawBody: string, signature: string, secret: string): boolean {
const [tPart, v1Part] = signature.split(',');
const parts = signature.split(',');
if (parts.length !== 2) return false;
const [tPart, v1Part] = parts;
const timestamp = tPart.split('=')[1];
const receivedSig = v1Part.split('=')[1];
if (!timestamp || !receivedSig) return false;
Comment on lines +48 to +59

@gemini-code-assist gemini-code-assist Bot Jun 12, 2026

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medium

The current implementation is fragile and not forward-compatible:\n\n1. Strict length check (parts.length !== 2): If Top.gg adds new fields to the signature header in the future (e.g., for versioning, metadata, or additional signatures), this check will fail and break the webhook integration for users copying this code.\n2. Order dependency: It assumes t is always the first part and v1 is the second part. If the order is reversed or changed, parsing will fail.\n\nParsing the header by splitting and matching keys in a loop is much more robust, order-independent, and forward-compatible.

  const parts = signature.split(',');\n  let timestamp: string | undefined;\n  let receivedSig: string | undefined;\n\n  for (const part of parts) {\n    const [key, ...valueParts] = part.split('=');\n    const value = valueParts.join('=');\n    if (key === 't') timestamp = value;\n    if (key === 'v1') receivedSig = value;\n  }\n\n  if (!timestamp || !receivedSig) return false;

const ts = parseInt(timestamp, 10);
const now = Math.floor(Date.now() / 1000);
if (isNaN(ts) || Math.abs(now - ts) > 300) return false;
const expected = crypto
.createHmac('sha256', secret)
.update(`${timestamp}.${rawBody}`)
.digest('hex');
return crypto.timingSafeEqual(Buffer.from(expected), Buffer.from(receivedSig));
const expectedBuf = Buffer.from(expected);
const receivedBuf = Buffer.from(receivedSig);
if (expectedBuf.length !== receivedBuf.length) return false;
return crypto.timingSafeEqual(expectedBuf, receivedBuf);
}
```

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