CVE-2022-3550Network attack vector

Server memory corruption via unchecked XKB length field

Published Oct 17, 2022 · Updated Apr 15, 2025

Buffer overflow in X.Org Server before 21.1.6 allows remote authenticated users to corrupt server memory through a malformed XKB request. The _GetCountedString function checks the complete counted string against the request buffer but fails to validate the initial two-byte length field before byte-swapping it. An authenticated X client using opposite byte order can make swaps() write outside the request buffer, corrupting server-process memory and interrupting the display service.

CVSS severity8.8
High
EPSS probability1.57%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in X.Org Server before 21.1.6 allows remote authenticated users to corrupt server memory through a malformed XKB request. The _GetCountedString function checks the complete counted string against the request buffer but fails to validate the initial two-byte length field before byte-swapping it. An authenticated X client using opposite byte order can make swaps() write outside the request buffer, corrupting server-process memory and interrupting the display service.

The record

CVE
CVE-2022-3550
Published
Oct 17, 2022
Updated
Apr 15, 2025
Vendor
X.Org
Product
X.Org Server
Classifications
CWE-120, CWE-119
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 17, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 15, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

X.Org · X.Org Serverversion=n/a

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5VulDBCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer

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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