How severe is CVE-2026-4430?

CVE-2026-4430 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-4430 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (1st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-4430?

CVE-2026-4430 affects Libreoffice. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-4430?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-4430 have an EU (EUVD) identifier?

Yes. CVE-2026-4430 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-28327.

When was CVE-2026-4430 published?

CVE-2026-4430 was published on 2026-05-07 and last updated on 2026-06-17.

CVE-2026-4430

CVE-2026-4430 is a high-severity vulnerability in Libreoffice with a CVSS 3.x base score of 7.8. 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-787.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v4: 5.4
EPSS exploit prediction: 0% (1st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-28327
Weakness: CWE-787
Affected product: Libreoffice
Published: 2026-05-07
Last modified: 2026-06-17

Description

Out-of-bounds write vulnerability in The Document Foundation LibreOffice via crafted OOXML documents with mismatched encryption salt parameters. This issue affects LibreOffice: from 26.2 before 26.2.3, from 25.8 before 25.8.7.

Frequently asked questions

What is CVE-2026-4430?: Out-of-bounds write vulnerability in The Document Foundation LibreOffice via crafted OOXML documents with mismatched encryption salt parameters. This issue affects LibreOffice: from 26.2 before 26.2.3, from 25.8 before 25.8.7.
How severe is CVE-2026-4430?: CVE-2026-4430 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-4430 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (1st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-4430?: CVE-2026-4430 affects Libreoffice. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-4430?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-4430 have an EU (EUVD) identifier?: Yes. CVE-2026-4430 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-28327.
When was CVE-2026-4430 published?: CVE-2026-4430 was published on 2026-05-07 and last updated on 2026-06-17.

References

https://www.libreoffice.org/about-us/security/advisories/cve-2026-4430

Affected products (1)

cpe:2.3:a:libreoffice:libreoffice:*:*:*:*:*:*:*:*

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