CVE-2026-26824 Information disclosure in n/a

Medium 6.5 Published 3 Jun 2026 Updated 23 Sep 2026

Attackers can cause crashes or disclose information by processing crafted XLS files due to uninitialized memory in the libxls library.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-26824?

CVE-2026-26824 is a medium-severity vulnerability in n/a, published on 3 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

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

Weakness: CWE-457

Which versions are affected by CVE-2026-26824?

It affects 1 product.

Products include Libxls Project Libxls.

How do I fix CVE-2026-26824?

Upgrade to a fixed version.

Is CVE-2026-26824 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-26824 exists.

Sources

Also known as DEBIAN-CVE-2026-26824, GHSA-hwmf-9wj8-35pw, JLSEC-2026-1301, UBUNTU-CVE-2026-26824.