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Fencer Vulns
medium 5.4

CVE-2026-6047 json

Heap buffer overflow in OOXML text box element import

published 2026-06-15 4 mo ago modified 2026-10-25 14 d ago also EUVD-2026-36737

cvss
5.4
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 4%
public exploits
0
none known

Summary

LibreOffice can import documents in the OOXML format (DOCX). A heap buffer overflow existed when replaying deferred parser events for a text box element. 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.

Patch / fix

  • The Document Foundation LibreOffice < 25.8.7, < 26.2.3
  • libreoffice Debian 14 4:26.2.3.2-2

debian advisories DEBIAN-CVE-2026-6047

  • libreoffice Ubuntu 26.04 LTS 4:26.2.4.2-0ubuntu0.26.04.2

ubuntu advisories UBUNTU-CVE-2026-6047

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libreoffice SLE Workstation Extension 15 SP7, SLE Module for Package Hub 15 SP7 26.2.5.1-150500.20.37.1

suse advisories SUSE-SU-2026:3140-1

  • libreoffice openSUSE Leap 16.0 26.8.1.1-bp160.1.1

opensuse advisories openSUSE-SU-2026:22216-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-6047 updated cvss 5.0

libreoffice: LibreOffice: Denial of service via heap buffer overflow in OOXML document processing

  • Red Hat Enterprise Linux 6 autocorr-af, autocorr-bg, autocorr-ca, autocorr-cs, autocorr-da, autocorr-de, +60 more Red Hat Enterprise Linux 7 autocorr-af, autocorr-bg, autocorr-ca, autocorr-cs, autocorr-da, autocorr-de, +105 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 autocorr-af, autocorr-bg, autocorr-ca, autocorr-cs, autocorr-da, autocorr-de, +98 more Red Hat Enterprise Linux 9 autocorr-af, autocorr-bg, autocorr-ca, autocorr-cs, autocorr-da, autocorr-de, +101 more
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.15% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 5.4 CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:P
CNA 4.0 5.4 CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • The Document Foundation LibreOffice

Classification

Weakness
  • CWE-787 Out-of-bounds Write
  • CWE-843 Access of Resource Using Incompatible Type

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.