What’s Vulnerable › Vulnerabilities

CVE-2026-26825

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-06-03 · updated 2026-09-23
• Weakness: CWE-908

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.

Affected products

• libxls: 1.6.3

References

• https://github.com/libxls/libxls/commit/9adf88f4e3b304e397f70ac189e70776edb6d5a3
• https://github.com/libxls/libxls/issues/153
• https://github.com/libxls/libxls/issues/156

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