Integer overflow in Qax-Os Excelize
CVE-2026-107224
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.
Vulnerability class: Integer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Qax-Os Excelize — versions >= 2.1.0, <= 2.11.0
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-107224?
- CVE-2026-107224 is a medium-severity vulnerability in Qax-Os Excelize, classified under Integer Overflow or Wraparound. CVSS score: 6.5/10. Published 2026-10-07.
- How severe is CVE-2026-107224?
- Medium severity. CVSS v3 base score is 6.5 out of 10.