CVE-2026-8356: Stack Buffer Overflow Vulnerability (CVSS 5.4)

Description

LibreOffice can import presentations in the legacy binary PPT format. A stack buffer overflow existed when importing a colour-replacement record. Two fixed-size colour tables were filled from the file, but the write position was not reset between the two passes over the record, so a file whose combined colour counts exceeded the table size wrote past the end of the tables on the stack. In fixed versions the unused second pass is no longer read into those tables.

Metrics

CVSS 4.0

5.4/10

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

EPSS Probability

0.15%

4.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

References

https://www.libreoffice.org/about-us/security/advisories/cve-2026-8356

Timeline

Published: Jun 15, 2026
Last Modified: Oct 25, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2026-8356?

LibreOffice can import presentations in the legacy binary PPT format. A stack buffer overflow existed when importing a colour-replacement record. Two fixed-size colour tables were filled from the file, but the write position was not reset between the two passes over the record, so a file whose combined colour counts exceeded the table size wrote past the end of the tables on the stack. In fixed versions the unused second pass is no longer read into those tables.

How severe is CVE-2026-8356?

CVE-2026-8356 has a CVSS score of 5.4/10 (MEDIUM severity). The EPSS model estimates a 0.15% probability of exploitation in the next 30 days.

How do I fix CVE-2026-8356?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

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