VYPR
Moderate severityNVD Advisory· Published Mar 10, 2026· Updated Mar 11, 2026

file-type affected by infinite loop in ASF parser on malformed input with zero-size sub-header

CVE-2026-31808

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.

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Affected packages

Versions sourced from the GitHub Security Advisory.

PackageAffected versionsPatched versions
file-typenpm
>= 13.0.0, < 21.3.121.3.1

Affected products

3

Patches

Vulnerability mechanics

References

4

News mentions

0

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