What’s Vulnerable › Vulnerabilities

CVE-2026-8357: Heap buffer overflow in Calc formula compilation

• Severity: high (CVSS 7.8 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: none known
• Published: 2026-06-15 · updated 2026-10-25
• Weakness: CWE-193

Description

LibreOffice Calc compiles cell formulas when opening a spreadsheet. A heap buffer overflow existed when compiling a very long formula made up of many opening tokens. The array that tracks nesting depth was allocated one element too small for that worst case, so such a formula wrote one element past its end. In fixed versions the array is sized to hold the largest possible nesting.

Affected products

• The Document Foundation LibreOffice: from 26.2 before < 26.2.4 — fixed in < 26.2.4

How to fix

Upgrade to a fixed version: The Document Foundation LibreOffice < 26.2.4. Check the vendor advisory for mitigations.

References

• https://www.libreoffice.org/about-us/security/advisories/cve-2026-8357
• https://access.redhat.com/errata/RHSA-2026:35839
• https://access.redhat.com/errata/RHSA-2026:36832
• https://access.redhat.com/errata/RHSA-2026:43423
• https://access.redhat.com/errata/RHSA-2026:43424
• https://access.redhat.com/errata/RHSA-2026:43425
• https://access.redhat.com/errata/RHSA-2026:43460
• https://access.redhat.com/errata/RHSA-2026:43461
• https://access.redhat.com/errata/RHSA-2026:46386
• https://access.redhat.com/errata/RHSA-2026:46387
• https://access.redhat.com/security/cve/CVE-2026-8357
• https://bugzilla.redhat.com/show_bug.cgi?id=2488964

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