Qax-os Excelize up to 2.11.0 Zip64 ReadZipReader UncompressedSize64 integer overflow

Summaryinfo

A vulnerability described as problematic has been identified in Qax-os Excelize up to 2.11.0. Affected by this vulnerability is the function ReadZipReader of the component Zip64 Handler. The manipulation of the argument UncompressedSize64 results in integer overflow. This vulnerability is known as CVE-2026-107224. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability was found in Qax-os Excelize up to 2.11.0. It has been classified as problematic. Affected is the function ReadZipReader of the component Zip64 Handler. The manipulation of the argument UncompressedSize64 with an unknown input leads to a integer overflow vulnerability. CWE is classifying the issue as CWE-190. The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. This is going to have an impact on availability. CVE summarizes:

Excelize is a Go language library for reading and writing Microsoft Excel spreadsheets. From 2.1.0 to 2.11.0, a Zip64 uncompressed size with the high bit set is converted from uint64 to a negative int64 before signed size-limit checks and allocation. ReadZipReader obtains UncompressedSize64 through FileInfo.Size and passes the wrapped negative value to readFile. When a crafted Zip64 entry declares an uncompressed size from 2^63 through 2^64-1 and the workbook is opened, the negative size bypasses unzip limits and reaches make as a negative capacity, allowing an attacker to panic during workbook opening. No fixed version is available as of this review.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-107224 since 10/07/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 10/07/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

• Qax-os

Name

• Excelize

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7
• 2.8
• 2.9
• 2.10
• 2.11.0

Website

• Product: https://github.com/qax-os/excelize/

CPE 2.3info

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