How severe is CVE-2026-26825?

CVE-2026-26825 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2026-26825 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-26825?

CVE-2026-26825 affects Libxls Project Libxls. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-26825?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-26825 have an EU (EUVD) identifier?

Yes. CVE-2026-26825 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-34179.

When was CVE-2026-26825 published?

CVE-2026-26825 was published on 2026-06-03 and last updated on 2026-06-17.

CVE-2026-26825

CVE-2026-26825 is a medium-severity vulnerability in Libxls Project Libxls with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-908.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 0% (12th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-34179
Weakness: CWE-908
Affected product: Libxls Project Libxls
Published: 2026-06-03
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-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 MemorySanitizer (MSAN) and can lead to undefined behavior, incorrect parsing logic, or potential information disclosure.
How severe is CVE-2026-26825?: CVE-2026-26825 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2026-26825 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-26825?: CVE-2026-26825 affects Libxls Project Libxls. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-26825?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-26825 have an EU (EUVD) identifier?: Yes. CVE-2026-26825 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-34179.
When was CVE-2026-26825 published?: CVE-2026-26825 was published on 2026-06-03 and last updated on 2026-06-17.

References

https://github.com/libxls/libxls/issues/156

Affected products (1)

cpe:2.3:a:libxls_project:libxls:1.6.3:*:*:*:*:*:*:*

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