Vulnerability in Libxls Project

CVE-2026-26824

libxls through version 1.6.3 contains a use of uninitialized memory vulnerability in the OLE container parser. Memory allocated for the Master Sector Allocation Table (MSAT) in read_MSAT() is not fully initialized before being consumed by ole2_validate_sector_chain(), which may result in application crashes or potential information disclosure when processing a crafted XLS file

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L.

EPSS exploit prediction

EPSS: 0.005 (36.8th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 36.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-26824: held from 0.002 to 0.005.

EPSS over last 30 days · oldest: 0.002 · newest: 0.005 · change: +0.002

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-26824?
CVE-2026-26824 is a medium-severity vulnerability in Libxls Project, classified under CWE-457. CVSS score: 6.5/10. Published 2026-06-03.
How severe is CVE-2026-26824?
Medium severity. CVSS v3 base score is 6.5 out of 10.