fkie_cve-2026-107213

Excelize is a Go language library for reading and writing Microsoft Excel spreadsheets. From 2.9.0 to 2.11.0, GetSlicers checks for ExtLst but dereferences ws.Drawing without checking whether the independently optional drawing element exists. File.GetSlicers reads ws.Drawing.RID after seeing a worksheet extLst element even when the independently optional worksheet drawing element is absent. When a crafted worksheet contains an extLst element without a drawing element and the application calls GetSlicers, the nil ws.Drawing pointer is dereferenced while resolving the drawing relationship, allowing an attacker to panic and terminate an unprotected process. No fixed version is available as of this review.

GHSA-r7x5-4969-99p7 — Excelize: Nil-pointer dereference in GetSlicers when a worksheet has extLst present but no drawing element

Affected: Go: github.com/xuri/excelize/v2

### Summary

GetSlicers guards only `if ws.ExtLst == nil { return }` (slicer.go:816-818) and then immediately dereferences `ws.Drawing.RID` with no nil check on ws.Drawing itself. `Drawing` and `ExtLst` are two independently optional child elements of <worksheet> in xl/worksheets/sheetN.xml, populated separately by encoding/xml depending on whether each tag is present. I executed a PoC: took a plain NewFile() workbook (no drawing, no slicer), saved it, then injected a bare `<extLst></extLst>` immediately before `</worksheet>` in xl/worksheets/sheet1.xml (no other change, no drawing element present) and called GetSlicers. Result: `runtime error: invalid memory address or nil pointer dereference`, confirmed at the ws.Drawing.RID line via stack trace.

### Reachability / who can trigger this

Unauthenticated: any application that opens an untrusted .xlsx and calls the public `File.GetSlicers(sheet)` API. The trigger is a single empty XML tag with no valid slicer or drawing content required at all, making it an even smaller/simpler payload than candidate 1.

### Proof of Concept / Reproduction

**Method:** 1) Reused the existing clone at C:\Users\vatsa\AppData\Local\Temp\claude\D--\59901fa2-b549-40e1-a433-30c8a3d01718\scratchpad\CVE-Hunt-10k\repos\qax-os__excelize (origin=https://github.com/qax-os/excelize.git, branch master up to date, commit e81f05008b33232151a58f06474fad5f70c4d060 dated 2026-09-27, `git describe`=v2.11.0-42-ge81f050, i.e. 42 commits past the v2.11.0 tag). 2)…

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fkie_cve-2026-107213

GHSA-r7x5-4969-99p7 — Excelize: Nil-pointer dereference in GetSlicers when a worksheet has extLst present but no drawing element