CVE-2026-8357
CVE-2026-8357 is a high-severity vulnerability 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-193.
Key facts
- Severity: High (CVSS 3.x base score 7.8)
- CVSS v4: 5.4
- EPSS exploit prediction: 0% (4th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-36739
- Weakness: CWE-193
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2026-8357?
- 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.
- How severe is CVE-2026-8357?
- CVE-2026-8357 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-2026-8357 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-8357?
- 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-2026-8357 have an EU (EUVD) identifier?
- Yes. CVE-2026-8357 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-36739.
- When was CVE-2026-8357 published?
- CVE-2026-8357 was published on 2026-06-15 and last updated on 2026-07-06.
References
- https://www.libreoffice.org/about-us/security/advisories/cve-2026-8357
- https://access.redhat.com/errata/RHSA-2026:35839
- https://access.redhat.com/security/cve/CVE-2026-8357
- https://bugzilla.redhat.com/show_bug.cgi?id=2488964
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-8357.json
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