CVE-2026-8358

Heap buffer overflow via change type confusion

Published Jun 15, 2026 · Updated Jun 15, 2026

Type confusion in LibreOffice Calc before 26.2.4 allows local users to corrupt heap memory by opening a crafted spreadsheet. The tracked-changes importer reuses a duplicate change identifier, casts the existing change object to a different, larger type, and writes beyond its allocation. Triggering the flaw requires passive interaction with attacker-controlled tracked-change records and can crash Calc or corrupt spreadsheet data held in process memory.

CVSS severityUnavailable
Unscored
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Type confusion in LibreOffice Calc before 26.2.4 allows local users to corrupt heap memory by opening a crafted spreadsheet. The tracked-changes importer reuses a duplicate change identifier, casts the existing change object to a different, larger type, and writes beyond its allocation. Triggering the flaw requires passive interaction with attacker-controlled tracked-change records and can crash Calc or corrupt spreadsheet data held in process memory.

The record

CVE
CVE-2026-8358
Published
Jun 15, 2026
Updated
Jun 15, 2026
Vendor
The Document Foundation
Product
LibreOffice
Classifications
CWE-843, CWE-787, CAPEC-44, 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

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-843Access of Resource Using Incompatible Type ('Type Confusion')
CWE-787Out-of-bounds Write
CAPEC-44Overflow Binary Resource File
T1204.002Malicious File

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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