n8n-io/n8n · warning · BadRequestError

Malformed binary data ID

Error message

Malformed binary data ID

What it means

BadRequestError (HTTP 400) 'Malformed binary data ID' thrown at binary-data.controller.ts:58 when the `id` contains no `:` separator — i.e. it is not in the required `<mode>:<path>` shape. `binaryDataId.indexOf(':')` returns -1.

Source

Thrown at packages/cli/src/controllers/binary-data.controller.ts:58

			await this.setContentHeaders(binaryDataId, 'download', res);
			return await this.binaryDataService.getAsStream(binaryDataId);
		} catch (error) {
			if (error instanceof FileNotFoundError) return res.status(404).end();
			if (error instanceof BadRequestError || error instanceof JsonWebTokenError)
				return res.status(400).end(error.message);
			else throw error;
		}
	}

	private validateBinaryDataId(binaryDataId: string) {
		if (!binaryDataId) {
			throw new BadRequestError('Missing binary data ID');
		}

		const separatorIndex = binaryDataId.indexOf(':');

		if (separatorIndex === -1) {
			throw new BadRequestError('Malformed binary data ID');
		}

		const mode = binaryDataId.substring(0, separatorIndex);

		if (!isValidNonDefaultMode(mode)) {
			throw new BadRequestError('Invalid binary data mode');
		}

		const path = binaryDataId.substring(separatorIndex + 1);

		if (path === '' || path === '/' || path === '//') {
			throw new BadRequestError('Malformed binary data ID');
		}
	}

	private async setContentHeaders(
		binaryDataId: string,
		action: 'view' | 'download',

View on GitHub (pinned to 5ac6606e81)

Solutions

1. Use the full binary ID `<mode>:<path>` emitted by the execution's `binary` field.
2. Construct IDs from the API response, not from execution metadata.

Example fix

// before
GET /binary-data?id=abc
// 400 Malformed binary data ID

// after
GET /binary-data?id=s3:exec-123/binary-0

function hasSeparator(id: string) { return id.includes(':'); }
// if (!hasSeparator(id)) throw new TypeError('id must be <mode>:<path>')

const isShapedId = (id: unknown): id is string =>
  typeof id === 'string' && id.indexOf(':') !== -1;

try { await get(req); } catch (e) { if (e instanceof BadRequestError && /Malformed/.test(e.message)) {/* rebuild id */} }

When it happens

Trigger: Passing a bare UUID, an execution ID, or any string without a colon as `id`. E.g. `?id=exec-123` or `?id=abc`.

Common situations: Clients confusing the execution ID with the binary data ID; legacy integrations that assumed raw IDs; copy-paste truncation dropping the path half.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• error.message
• Missing binary data ID
• Invalid binary data mode
• Content not viewable
• output.error.errors[0]

AI-assisted analysis of n8n-io/n8n@5ac6606e81 (2026-08-12). Data as JSON: /api/errors/f51ec3ed060ee23e. Report an issue: GitHub.