# CVE-2026-4430: Out-of-bounds write vulnerability in The Document Foundation LibreOffice via crafted OOXML documents with mismatched…

Source: https://junglewise.ai/threats/cve-2026-4430-out-of-bounds-write-vulnerability-in-the-document-foundation  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-07  
License: CC BY 4.0 with a link back

CVE-2026-4430 · Severity: high · CVSS 7.8 · Published 2026-05-07

Out-of-bounds write vulnerability in The Document Foundation LibreOffice via crafted OOXML documents with mismatched encryption salt parameters.

This issue affects LibreOffice: from 26.2 before 26.2.3, from 25.8 before 25.8.7.

Technologies: [LibreOffice](https://junglewise.ai/threats/technologies/libreoffice-libreoffice). Vendors: [LibreOffice](https://junglewise.ai/threats/vendors/libreoffice).

## Quick answers

**Is CVE-2026-4430 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-4430 being exploited in the wild.

**How severe is CVE-2026-4430?** High severity, with a CVSS score of 7.8, published 7 May 2026.

**Which products and versions are affected?** LibreOffice. The advisory does not name versions.

**Is there a fix for CVE-2026-4430?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**Am I affected by CVE-2026-4430?** Check whether you run LibreOffice. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- LibreOffice

## Related threats

- [LibreOffice heap buffer overflow in dBASE index import](https://junglewise.ai/threats/cve-2026-76181-libreoffice-includes-a-dbase-database-driver-which-reads-dbase)
- [LibreOffice environment and INI file variable expansion information leak](https://junglewise.ai/threats/cve-2026-63270-urls-could-be-constructed-which-expanded-environment-variable-or)
- [LibreOffice out of bounds read in PICT image import](https://junglewise.ai/threats/cve-2026-63279-libreoffice-can-import-pict-images-which-may-be-embedded-in)
- [LibreOffice stack buffer overflow in CFF to Type 1 font conversion](https://junglewise.ai/threats/cve-2026-63276-libreoffice-converts-cff-fonts-to-type-1-when-it-subsets-a-font)
- [LibreOffice stack buffer overflow in CFF font hint handling](https://junglewise.ai/threats/cve-2026-63275-libreoffice-can-read-cff-fonts-which-may-be-embedded-in-documents)