# CVE-2026-63274: LibreOffice Draw heap buffer overflow in PDF stream import

Source: https://junglewise.ai/threats/cve-2026-63274-libreoffice-draw-can-import-pdf-documents-a-heap-buffer-overflow  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-22. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-63274 · Severity: info · Published 2026-09-22

LibreOffice Draw, which allows users to open and edit PDF documents, contains a heap buffer overflow vulnerability when processing PDF streams. An attacker who crafts a malicious PDF with an incorrect stream length declaration could cause a buffer overflow, potentially leading to code execution when the document is imported. The vulnerability is fixed in LibreOffice 26.2.5.

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

## Quick answers

**Is CVE-2026-63274 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-63274 being exploited in the wild.

**How severe is CVE-2026-63274?** Informational severity, published 22 September 2026.

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

**Is there a fix for CVE-2026-63274?** A patch was published on 2026-09-21: Fixed in LibreOffice 26.2.5 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-63274 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2026-63274?** Check whether you run LibreOffice Draw 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.

## Technical details

A heap buffer overflow exists in PDF stream object import when the declared stream length in the PDF dictionary is not validated against the actual bytes present. The stream copying operation uses the untrusted length value without bounds checking, causing a write past the buffer end. The fix clamps the declared length to the number of bytes actually read from the file.

## Affected products

- LibreOffice Draw before 26.2.5

## Timeline

- 2026-09-21: disclosed
- 2026-09-21: patched: Fixed in LibreOffice 26.2.5

## References

- [https://www.libreoffice.org/about-us/security/advisories/cve-2026-63274](https://www.libreoffice.org/about-us/security/advisories/cve-2026-63274)

## Related threats

- [LibreOffice Draw heap buffer overflow in PDF import encryption handling](https://junglewise.ai/threats/cve-2026-63273-libreoffice-draw-can-import-pdf-documents-a-heap-buffer-overflow)