CVE-2026-93542Hinoki check available

X client crash via malformed XI2 classes

Published Sep 24, 2026 · Updated Sep 24, 2026

Out-of-bounds read in X.Org libXi before 1.8.4 allows attackers controlling an X server to crash X clients with malformed XI2 class data. The size_classes() and copy_classes() routines traverse server-supplied class records without adequately bounding each record against the reply length. Exploitation requires an affected client to process a malicious server reply, and the documented consequence is a client crash.

CVSS severityUnavailable
Unscored
EPSS probability0.25%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Out-of-bounds read in X.Org libXi before 1.8.4 allows attackers controlling an X server to crash X clients with malformed XI2 class data. The size_classes() and copy_classes() routines traverse server-supplied class records without adequately bounding each record against the reply length. Exploitation requires an affected client to process a malicious server reply, and the documented consequence is a client crash.

The record

CVE
CVE-2026-93542
Published
Sep 24, 2026
Updated
Sep 24, 2026
Vendor
The X11 Project
Product
libXi
Classifications
Unavailable
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 24, 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=0 <1.8.4

What conditions does exploitation require?

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

What is affected?

The X11 Project · libXiversion=0 <1.8.4

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

No sourced classifications are available.

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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