SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2026-26825

A use-of-uninitialized memory vulnerability exists in libxls 1.6.3 when parsing malformed XLS files.

MEDIUM 5.3EPSS 0.21%

Does this matter?

Lower severity and a low EPSS score (0.21%). Track it; it rarely justifies an emergency change on its own.

Description

A use-of-uninitialized memory vulnerability exists in libxls 1.6.3 when parsing malformed XLS files. The issue is reachable via xls_parseWorkBook() and is triggered by uninitialized heap memory originating from the OLE layer (ole2_read). The flaw is detectable with MemorySanitizer (MSAN) and can lead to undefined behavior, incorrect parsing logic, or potential information disclosure.

CVSS 3.1
5.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
EPSS
0.21% probability · 12th percentile
CISA KEV
Not listed
Weakness
CWE-908
Affected
libxls project/libxls
Source
cve@mitre.org

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.