CVE-2026-8357

Code execution via formula nesting off-by-one

Published Jun 15, 2026 · Updated Jun 15, 2026

Heap buffer overflow in LibreOffice Calc 26.2 through 26.2.3 allows attackers to execute code when a crafted spreadsheet is opened. Calc's formula compiler allocates its nesting-depth array one element too small for the maximum number of opening tokens, causing a one-element out-of-bounds write. Exploitation requires a user to open the spreadsheet and can corrupt memory within the LibreOffice process.

CVSS severity7.8
High
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer overflow in LibreOffice Calc 26.2 through 26.2.3 allows attackers to execute code when a crafted spreadsheet is opened. Calc's formula compiler allocates its nesting-depth array one element too small for the maximum number of opening tokens, causing a one-element out-of-bounds write. Exploitation requires a user to open the spreadsheet and can corrupt memory within the LibreOffice process.

The record

CVE
CVE-2026-8357
Published
Jun 15, 2026
Updated
Jun 15, 2026
Vendor
The Document Foundation
Product
LibreOffice
Classifications
CWE-193, CWE-787, CWE-131, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=26.2 << 26.2.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

The Document Foundation · LibreOfficeversion=26.2 << 26.2.4

Published CVSS scores

7.8Red Hat Security Data ProgramCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
5.4The Document FoundationCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-193Off-by-one Error
CWE-787Out-of-bounds Write
CWE-131Incorrect Calculation of Buffer Size
T1204.002Malicious File

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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