vulnerability / NVI-00012938 / Revision 1
adm-zip: getDataAsync() bypasses the maxOutputLength size guard enforced by the synchronous getData() path
GitHub lists this reviewed advisory for adm-zip. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
5.3 medium
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
adm-zip
source listed<= 0.6.0
### 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, central
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
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04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
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- GHSA-c6fg-446q-cg94 ↗
GitHub Advisory Database · vendor advisory
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Public revision history
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- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.