CVE-2026-8357 is a vulnerability in LibreOffice Calc where a heap buffer overflow occurs during formula compilation, enabling arbitrary code execution. Red Hat Product Security has released an update for libreoffice packages in Red Hat Enterprise Linux 8 to remediate this issue. The advisory classifies the security impact as Important. The vulnerability is tracked under CWE-131 (Incorrect Calculation of Buffer Size). The fix is included in libreoffice version 6.4.7.2-21.el8_10 and related packages for RHEL 8 variants. No known exploits in the wild have been reported at the time of the advisory.

Successful exploitation of this vulnerability could allow an attacker to execute arbitrary code on the affected system via specially crafted spreadsheet formulas in LibreOffice Calc. This could lead to system compromise or unauthorized actions under the privileges of the user running LibreOffice. The advisory rates the impact as Important, indicating a high severity but not critical. No active exploitation has been reported.

Red Hat has released an official security update for libreoffice packages in Red Hat Enterprise Linux 8 to address this vulnerability. Users should apply the update as described in the Red Hat advisory RHSA-2026:35839 and the referenced article https://access.redhat.com/articles/11258. Applying this update will remediate the heap buffer overflow and prevent arbitrary code execution via formula compilation. No additional mitigation steps are indicated by the vendor.