Vulnerability · Published Mar 10, 2026 · Assigned by GitHub_M
CVE-2026-31808file-type affected by infinite loop in ASF parser on malformed input with zero-size sub-header
Medium 5.3
In plain English
A medium-severity infinite loop in file-type from sindresorhus. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
file-type detects the file type of a file, stream, or data. Prior to 21.3.1, a denial of service vulnerability exists in the ASF (WMV/WMA) file type detection parser. When parsing a crafted input where an ASF sub-header has a size field of zero, the parser enters an infinite loop. The payload value becomes negative (-24), causing tokenizer.ignore(payload) to move the read position backwards, so the same sub-header is read repeatedly forever. Any application that uses file-type to detect the type of untrusted/attacker-controlled input is affected. An attacker can stall the Node.js event loop with a 55-byte payload. Fixed in version 21.3.1.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | file-type | 21.3.1 | GHSA-5v7r-6r5c-r473 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| sindresorhus | file-type | >= 13.0.0, < 21.3.1 |
Weakness: CWE-835 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L