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PatchSiren cyber security CVE debrief

CVE-2026-6047 The Document Foundation CVE debrief

CVE-2026-6047 is a medium-severity vulnerability in LibreOffice, a popular open-source office suite. The vulnerability is caused by a heap buffer overflow that occurs when replaying deferred parser events for a text box element in the OOXML format (DOCX).

Vendor
The Document Foundation
Product
LibreOffice
CVSS
MEDIUM 5.4
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-15
Original CVE updated
2026-06-15
Advisory published
2026-06-15
Advisory updated
2026-06-15

Who should care

Users of LibreOffice, especially those who handle DOCX files, should be aware of this vulnerability. The vulnerability has a CVSS score of 5.4 and is considered medium-severity.

Technical summary

The vulnerability is caused by a heap buffer overflow that occurs when replaying deferred parser events for a text box element in the OOXML format (DOCX). A handler object was assumed to be of one type and written to at that type's field layout, but it could be a smaller object, so the write landed past the end of the allocation. In fixed versions, the type is checked before the write.

Defensive priority

Medium

Recommended defensive actions

  • Update LibreOffice to the latest version.
  • Be cautious when opening DOCX files from untrusted sources.

Evidence notes

The CVE record was obtained from the official CVE website [cve-org]. The vulnerability details were obtained from the NVD database [nvd]. The vendor information was obtained from the LibreOffice security advisory [ref-4].

Sources and references

Verified primary and authoritative sources

  • CVE-2026-6047 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-6047

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-6047 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-6047

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.