adm-zip: getDataAsync() bypasses the maxOutputLength size guard enforced by the synchronous getData() path

### Summary adm-zip enforces a `maxOutputLength` guard against decompression bombs on its synchronous `getData()` path, but the equivalent asynchronous `getDataAsync()` path does not enforce it — it accumulates and returns the entire decompressed output regardless of the entry's declared size. An application that checks an entry's declared size before deciding to process it, then reads the entry via `getDataAsync()` (a completely ordinary, often-recommended choice for I/O in Node.js), gets none of the protection it believes it has. ### Details - `methods/inflater.js:3-10` passes `{maxOutputLength: expectedLength}` to `inflateRawSync`, which Node enforces. - `methods/inflater.js:12-31` passes the same option to `createInflateRaw` but never enforces it on the streaming path — it just accumulates every chunk and allocates a final Buffer of whatever size resulted. ### PoC ```js const AdmZip = require('adm-zip'); const zip = new AdmZip(); zip.addFile('p', Buffer.alloc(64 * 1024 * 1024, 0x41)); // 64 MiB const raw = Buffer.from(zip.toBuffer()); // patch the local + central declared uncompressed size to 1 byte raw.writeUInt32LE(1, localHeaderSizeOffset); raw.writeUInt32LE(1, centralHeaderSizeOffset); const entry = new AdmZip(raw).getEntry('p'); entry.getData(); // throws: ERR_BUFFER_TOO_LARGE: Cannot create a Buffer larger than 1 bytes entry.getDataAsync((data, error) => { ... }); // returns the full 67,108,864-byte buffer, error is undefined ``` ### Impact An application that validates a declared size before reading an entry, then uses the async API, gets no protection against a high-ratio DEFLATE payload. Repeated or larger requests could contribute to memory exhaustion.

Source published

29 Sep 2026 23:10:32 UTC

Source modified

21 Oct 2026 10:57:29 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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