# CVE-2026-107218: Excelize: RIGHT() on supplementary-plane text slices with a negative index and panics

> An attacker can cause a denial of service by triggering a panic in the Excelize library through malformed RIGHT formula arguments on supplementary-plane text.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 7 Oct 2026
- **Updated:** 7 Oct 2026
- **Also known as:** GHSA-8jjq-8j9w-m2v6

## What is CVE-2026-107218?

CVE-2026-107218 is a medium-severity denial of service vulnerability in qax-os excelize, published on 7 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Excelize is a Go language library for reading and writing Microsoft Excel spreadsheets. From 2.10.1 to 2.11.0, RIGHT validates the requested length with UTF-16 code-unit counts but slices a rune array using Unicode code-point counts. RIGHT reaches leftRight through CalcCellValue, where countUTF16String validates one unit but utf8.RuneCountInString supplies the slice index in another. When RIGHT evaluates supplementary-plane text with a requested character count between the rune count and UTF-16 code-unit count, the inconsistent units produce a negative rune-slice index, allowing an attacker to panic during formula evaluation. No fixed version is available as of this review.

Weakness: CWE-129 (Improper Validation of Array Index)

## Which versions are affected by CVE-2026-107218?

2 open source packages ship an affected version, including github.com/xuri/excelize/v2. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/xuri/excelize/v2` | Go | From 2.10.1 | 2.11.1-0.20260908032718-ecd99d761fe0 |
| `github.com/xuri/excelize/v2` | Go | From 2.10.1 | 2.11.1-0.20260908032718-ecd99d761fe0 |

Products: Excelize Excelize.

## How do I fix CVE-2026-107218?

Upgrade github.com/xuri/excelize/v2 to 2.11.1-0.20260908032718-ecd99d761fe0 or later.

## Is CVE-2026-107218 being exploited?

There is no known exploitation of CVE-2026-107218 in the wild and no public exploit code.

## Other vulnerabilities in qax-os excelize

- [CVE-2026-107211](https://insights.sbomify.com/CVE-2026-107211/): Excelize: Unchecked pivot-cache field index in extractPivotTableFields causes unrecoverable panic (high 8.7)
- [CVE-2026-107213](https://insights.sbomify.com/CVE-2026-107213/): Excelize: Nil-pointer dereference in GetSlicers when a worksheet has extLst present but no drawing element (high 8.7)
- [CVE-2026-59161](https://insights.sbomify.com/CVE-2026-59161/): Excelize: Streaming GetRows row-bound bypass causes attacker-controlled allocation (high 8.7)
- [CVE-2026-107212](https://insights.sbomify.com/CVE-2026-107212/): Excelize: Unbounded row number in Rows.Columns makes GetRows and the Rows iterator loop for days (high 7.5)
- [CVE-2026-107214](https://insights.sbomify.com/CVE-2026-107214/): Excelize Decrypt: unrecoverable panics on malformed OLE/CFB encrypted workbooks (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-107218 and fix it if it is affected.

What it is: CVE-2026-107218 is a medium-severity denial of service vulnerability in qax-os excelize, published on 7 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-107218 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/xuri/excelize/v2 (Go): affected from 2.10.1; fixed in 2.11.1-0.20260908032718-ecd99d761fe0
- github.com/xuri/excelize/v2 (Go): affected from 2.10.1; fixed in 2.11.1-0.20260908032718-ecd99d761fe0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-107218/ (Markdown: https://insights.sbomify.com/CVE-2026-107218/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-107218
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-107218
- OSV: https://osv.dev/vulnerability/CVE-2026-107218

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-107218/
Summaries are generated and may contain mistakes; the official description above is the record.