Vulnerability · Published Oct 7, 2026 · Assigned by GitHub_M
CVE-2026-107218Excelize: RIGHT() on supplementary-plane text slices with a negative index and panics
Medium 5.3
In plain English
A medium-severity security flaw in excelize from qax-os. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/xuri/excelize/v2 | 2.11.1-0.20260908032718-ecd99d761fe0 | GHSA-8jjq-8j9w-m2v6 |
| Go | github.com/xuri/excelize/v2 | 2.11.1-0.20260908032718-ecd99d761fe0 | GO-2026-6675 |
Affected products (as reported)
Weakness: CWE-129 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
References
- https://github.com/qax-os/excelize/security/advisories/GHSA-8jjq-8j9w-m2v6 x_refsource_CONFIRM
- https://github.com/qax-os/excelize/pull/2390 x_refsource_MISC
- https://github.com/qax-os/excelize/commit/ecd99d761fe0489f1ed308e2f7dc2e0502d1a396 x_refsource_MISC