---
id: "CVE-2026-107215"
kind: "vulnerability"
aliases: ["CVE-2026-107215", "GHSA-x2q3-8cjh-766f", "GO-2026-6689"]
title: "Panic and memory exhaustion via unbounded CFB stream allocation in github.com/xuri/excelize"
severity: "high"
cvss: 7.5
epss: 0.00228
exploited: false
status: "open"
category: "package"
products: [{"name": "github.com/360EntSecGroup-Skylar/excelize/v2", "fixed": [], "affected": ">= 2.3.1", "ecosystem": "go"}, {"name": "github.com/xuri/excelize/v2", "fixed": ["2.11.1-0.20260912113515-5f636f9dcde5"], "affected": "< 2.11.1-0.20260912113515-5f636f9dcde5", "ecosystem": "go"}]
ecosystems: ["go"]
tags: ["backend", "excelize", "file-upload", "go", "package"]
not_affected_if: ["no-untrusted-xlsx-input", "version-outside-2.3.1-to-2.11.0"]
published_at: "2026-10-07T18:17:19+00:00"
first_seen_at: "2026-10-23T19:13:08+00:00"
updated_at: "2026-10-23T19:56:13+00:00"
sources: [{"source": "govuln", "url": "https://pkg.go.dev/vuln/GO-2026-6689", "first_seen_at": "2026-10-23T19:13:08+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-107215", "first_seen_at": "2026-10-23T19:13:43+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-107215", "first_seen_at": "2026-10-23T19:35:23+00:00"}]
---

# Panic and memory exhaustion via unbounded CFB stream allocation in github.com/xuri/excelize

Excelize, a Go library for reading and writing Excel files, allocates memory based on a size field in a crafted OLE compound file without validating it first. An attacker who supplies such a file can crash the process with a panic or exhaust its memory.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- go:github.com/360EntSecGroup-Skylar/excelize/v2 affected >= 2.3.1 fixed ?
- go:github.com/xuri/excelize/v2 affected < 2.11.1-0.20260912113515-5f636f9dcde5 fixed 2.11.1-0.20260912113515-5f636f9dcde5

## How to check

Run `go list -m github.com/xuri/excelize/v2` in each service and check the version against the affected range.
Search go.sum for `excelize` to find transitive copies, including the older github.com/360EntSecGroup-Skylar/excelize/v2 path.
If services parse user-uploaded .xlsx files, flag them as exposed.

## Fix

Move github.com/xuri/excelize/v2 to 2.11.1-0.20260912113515-5f636f9dcde5 or later, per the product data.
The description says no fixed version is available, which conflicts with that data; confirm before relying on the upgrade. Until then, reject or sandbox untrusted spreadsheet input.

## Timeline

- 2026-10-23T19:13:08+00:00 govuln https://pkg.go.dev/vuln/GO-2026-6689
- 2026-10-23T19:13:43+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-107215
- 2026-10-23T19:35:23+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-107215

## From the sources

Excelize is a Go language library for reading and writing Microsoft Excel spreadsheets. From 2.3.1 to 2.11.0, extractPart allocates a byte slice directly from an attacker-controlled CFB directory-entry size before validating the sector chain or size domain. extractPart trusts the CFB directory entry streamSize for EncryptionInfo and EncryptedPackage allocations before validating the stream. When a crafted OLE compound file declares a negative or extremely large EncryptionInfo or EncryptedPackage stream size, the declared size reaches make with a negative length or forces a multi-gigabyte allocation, allowing an attacker to panic or exhaust process memory. No fixed version is available as of this review.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_