CVE-2026-31808CWE-835

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

Medium · published March 10, 2026

CVSS v3.1
5.3
EPSS
0%
Percentile
36.7
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS v4.0
Not supplied
EPSS
0.00434 · 36.7th percentile
Weakness
CWE-835 · Loop with Unreachable Exit Condition ('Infinite Loop')
Published
2026-03-10T21:01Z
EPSS history
Timeline
  • 10 MAR 21:01Z
    file-type affected by infinite loop in ASF parser on malformed input with zero-size sub-header
    cvelistv5