CVE-2026-32256

music-metadata's ASF parser (parseExtensionObject() in lib/asf/AsfParser.ts:112-158) enters an infinite loop when a sub-object inside the ASF Header Extension Object has objectSize = 0.

Root Cause

When objectSize is 0:

1. remaining = 0 - 24 = -24
2. tokenizer.ignore(-24) moves the read position backward by 24 bytes
3. extensionSize -= 0 (loop counter never decreases)
4. while (extensionSize > 0) never exits
5. The same 24-byte header is re-read infinitely

This is the same pattern as CVE-2026-31808 (GHSA-5v7r-6r5c-r473) in file-type, strtok3's AbstractTokenizer.ignore() accepts negative values without validation.

Affected Methods

• parseFile(), HANGS (FileTokenizer inherits vulnerable ignore())
• parseBuffer(), HANGS (BufferTokenizer inherits vulnerable ignore())
• parseStream(), NOT affected (ReadStreamTokenizer has own ignore() that throws RangeError)

A 100-byte crafted .asf file permanently hangs any application using parseFile() or parseBuffer(). music-metadata has 2.2M weekly npm downloads.

CVE-2026-32256 has a CVSS score of 7.5 (High). 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 (11.12.3); upgrading removes the vulnerable code path.

Kodem intelligence

Validate objectSize >= minimumHeaderSize before calculating the payload. Or fix strtok3's AbstractTokenizer.ignore() to reject negative values.

1. What is CVE-2026-32256? CVE-2026-32256 is a high-severity security vulnerability in music-metadata (npm), affecting versions <= 11.12.1. It is fixed in 11.12.3.
2. How severe is CVE-2026-32256? CVE-2026-32256 has a CVSS score of 7.5 (High). 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.
3. Which versions of music-metadata are affected by CVE-2026-32256? music-metadata (npm) versions <= 11.12.1 is affected.
4. Is there a fix for CVE-2026-32256? Yes. CVE-2026-32256 is fixed in 11.12.3. Upgrade to this version or later.
5. Is CVE-2026-32256 exploitable, and should I be worried? Whether CVE-2026-32256 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
6. What actually determines whether CVE-2026-32256 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.
7. How do I fix CVE-2026-32256? Upgrade music-metadata to 11.12.3 or later.