CVE-2026-63276Hinoki check available

Process memory corruption via unchecked CFF writes

Published Sep 22, 2026 · Updated Sep 22, 2026

Stack buffer overflow in LibreOffice 26.2 through 26.2.4 allows attackers to corrupt process memory during PDF export. The CFF-to-Type 1 converter writes glyph operators into a fixed-size stack buffer without checking its remaining capacity, so a glyph emitting enough operators writes past its end. Triggering the flaw requires a document with an embedded CFF font and a user-initiated PDF export; no stronger consequence than process-memory corruption is documented.

CVSS severityUnavailable
Unscored
EPSS probability0.19%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Stack buffer overflow in LibreOffice 26.2 through 26.2.4 allows attackers to corrupt process memory during PDF export. The CFF-to-Type 1 converter writes glyph operators into a fixed-size stack buffer without checking its remaining capacity, so a glyph emitting enough operators writes past its end. Triggering the flaw requires a document with an embedded CFF font and a user-initiated PDF export; no stronger consequence than process-memory corruption is documented.

The record

CVE
CVE-2026-63276
Published
Sep 22, 2026
Updated
Sep 22, 2026
Vendor
The Document Foundation
Product
LibreOffice
Classifications
T1204.002
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 22, 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 << 26.2.5

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

The Document Foundation · LibreOfficeversion=26.2 << 26.2.5

Published CVSS scores

No CVSS assessment is available in this record.

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.

Activity data is delayed. The latest report is Sep 28, 2026.

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

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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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