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Vulnerabilities

Vulnerability · CVE-2026-26825

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

Published Jun 3, 2026 · catalog updated Sep 23, 2026 · libxls project

Check if you run it

No confirmed exploitation is on record for CVE-2026-26825. EPSS is 0.40%. Act only if a listed version of libxls project is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium5.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.40%
Remediation
Not established
Affected products
cpe libxls project/libxls

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe libxls project/libxls1.6.3

How to fix CVE-2026-26825

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-26825. EPSS is 0.40%. Act only if a listed version of libxls project is installed.

Which versions are affected?

Compare what you have installed with libxls project/libxls 1.6.3. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-908: Use of Uninitialized Resource. EPSS 0.40%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jun 3, 2026 · NIST NVD

    Detected

    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.

  2. Sep 23, 2026 · NIST NVD

    Updated

    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.

Sources

  • CVE.orgVulnerability recordCVE-2026-26825

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-26825

    30-day exploitation probability 0.4%

    first.org
  • NIST NVDVulnerability recordCVE-2026-26825

    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 MemorySanitize

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.