thejoshwolfe yauzl up to 3.2.0 ZIP File getLastModDate off-by-one

Summaryinfo

A vulnerability was found in thejoshwolfe yauzl up to 3.2.0. It has been rated as problematic. This vulnerability affects the function getLastModDate of the component ZIP File Handler. Performing a manipulation results in off-by-one. This vulnerability is known as CVE-2026-31988. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as problematic has been found in thejoshwolfe yauzl up to 3.2.0. This affects the function getLastModDate of the component ZIP File Handler. The manipulation with an unknown input leads to a off-by-one vulnerability. CWE is classifying the issue as CWE-193. A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value. This is going to have an impact on availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-31988 since 03/10/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 302194 (Linux Distros Unpatched Vulnerability : CVE-2026-31988), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 3.2.1 eliminates this vulnerability. Applying the patch c4695215b05c6adffda613b9051a2a85429b33fe is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (302194). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

• thejoshwolfe

Name

• yauzl

Version

• 3.0
• 3.1
• 3.2.0

License

• open-source

Website

• Product: https://github.com/thejoshwolfe/yauzl/

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