# CVE-2026-63270: LibreOffice environment and INI file variable expansion information leak

Source: https://junglewise.ai/threats/cve-2026-63270-urls-could-be-constructed-which-expanded-environment-variable-or  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-05. Updated: 2026-10-05  
License: CC BY 4.0 with a link back

CVE-2026-63270 · Severity: info · Published 2026-10-05

LibreOffice is an office productivity suite that opens documents containing links and embedded data. Attackers can craft documents with specially-constructed URLs that cause LibreOffice to expand environment variables and INI file values, potentially exfiltrating sensitive configuration data to remote servers when a user opens the document. This affects XForms instance data and Calc's CSV and SQL data providers.

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

## Quick answers

**Is CVE-2026-63270 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-63270 being exploited in the wild.

**How severe is CVE-2026-63270?** Informational severity, published 5 October 2026.

**Which products and versions are affected?** LibreOffice before 26.2.5 and before 26.8.0.

**Is there a fix for CVE-2026-63270?** Yes: fixed in LibreOffice 26.2.5, LibreOffice 26.8.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-63270 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-63270?** Check whether you run LibreOffice at an affected version. 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.

## How to fix

- Fixed in LibreOffice 26.2.5, LibreOffice 26.8.0

## Technical details

URLs in XForms instance data and Calc CSV/SQL data providers can undergo environment variable and INI file value expansion, allowing internal scheme URLs to be processed and their expanded values transmitted to attacker-controlled servers. The vulnerability exists because an earlier fix for CVE-2024-12426 did not address all code paths where documents supply URLs. The fix restricts such internal scheme URLs when originating from document content.

## Affected products

- LibreOffice LibreOffice before 26.2.5 and before 26.8.0

## Timeline

- 2026-10-05: disclosed

## References

- [https://www.libreoffice.org/about-us/security/advisories/cve-2026-63270](https://www.libreoffice.org/about-us/security/advisories/cve-2026-63270)

## 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 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)
- [LibreOffice heap buffer overflow in WMF text record import](https://junglewise.ai/threats/cve-2026-63272-libreoffice-can-import-wmf-graphics-which-may-be-embedded-in)