CVE-2026-31808: file-type detects the file type of a file, stream, or data

Q: How do I fix CVE-2026-31808?

file-type: upgrade to 21.3.1. Exact commands for each OS are on this page.

Q: Is CVE-2026-31808 being exploited?

CVE-2026-31808 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-31808 affect?

CVE-2026-31808 affects file-type. Severity is medium (CVSS 5.3). 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

Q: How urgent is CVE-2026-31808?

Priority 31/100. Remotely exploitable, no login, no user action

Routine

MEDIUM 5.3REMOTEUPGRADE

CVE-2026-31808 is a medium-severity flaw (CVSS 5.3) affecting file-type. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 72%)
CISA exploited list	No
Weakness	CWE-835
Published	2026-03-10
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: sindresorhus

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-10 21:16 UTCPublished CVE record published
2026-06-17 10:34 UTCUpdated Record last modified

sindresorhus file-type UPGRADE

Affected: >= 13.0.0 and < 21.3.1

Fixed in: 21.3.1

Safe to downgrade to: a release before 13.0.0

1. Check installed version

npm ls file-type

2. UPGRADE to 21.3.1

npm install file-type@">=21.3.1"

3. If no update is available yet, DOWNGRADE to a release before 13.0.0

npm view file-type versions npm install file-type@"<13.0.0"

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-31808?

file-type: upgrade to 21.3.1. Exact commands for each OS are on this page.

Is CVE-2026-31808 being exploited?

CVE-2026-31808 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-31808 affect?

CVE-2026-31808 affects file-type. Severity is medium (CVSS 5.3). 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

How urgent is CVE-2026-31808?

Priority 31/100. Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-32630 MEDIUM 5.3 UPGRADE file-type detects the file type of a file, stream, or data

References

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