Excelize: A Zip64 uncompressed-size of 2^63 panics OpenFile/OpenReader

[ Why it matters ]Priority signals

• Public proof-of-concept exploit exists (CISA SSVC)

[ Description ]Official 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.

[ Fixes ]Fixes and patches

• github.com/xuri/excelize/v2 2.11.1-0.20260805032953-db93f8d89de7Fixed version · GitHub Advisories · go package github.com/xuri/excelize/v2: upgrade to 2.11.1-0.20260805032953-db93f8d89de7 or later (affected >= 2.1.0, < 2.11.1-0.20260805032953-db93f8d89de7)
• Patch on github.comVendor patch or bulletin · NVD · Reference tagged 'Patch' by NVD
• Patch on github.comVendor patch or bulletin · NVD · Reference tagged 'Patch' by NVD

[ Packages ]Affected open-source packages

• github.com/xuri/excelize/v2 goAffected >= 2.1.0, < 2.11.1-0.20260805032953-db93f8d89de7 · fixed in 2.11.1-0.20260805032953-db93f8d89de7 · GHSA-fw94-4wwp-w8pw

[ References ]References

• github.com/qax-os/excelize/commit/db93f8d89de71589069a54d1b998af02e3c5f7cdPatch
• github.com/qax-os/excelize/pull/2369Issue TrackingPatch
• github.com/qax-os/excelize/security/advisories/GHSA-fw94-4wwp-w8pwExploitVendor Advisory