CVE-2023-28484Public exploitNetwork attack vector

Application crash via invalid XSD schema

Published Apr 24, 2023 · Updated May 30, 2025

NULL pointer dereference in libxml2 before 2.10.4 allows attackers to crash an application by supplying an invalid XSD schema. xmlSchemaFixupComplexType enters complex-content processing when baseType->subtypes is NULL because its guard tests only dummySequence, and subsequent processing dereferences the absent subtype. Reachability requires a consuming application to parse attacker-controlled XSD content, and the bounded effect is termination of that process.

CVSS severity6.5
Medium
EPSS probability1.09%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in libxml2 before 2.10.4 allows attackers to crash an application by supplying an invalid XSD schema. xmlSchemaFixupComplexType enters complex-content processing when baseType->subtypes is NULL because its guard tests only dummySequence, and subsequent processing dereferences the absent subtype. Reachability requires a consuming application to parse attacker-controlled XSD content, and the bounded effect is termination of that process.

The record

CVE
CVE-2023-28484
Published
Apr 24, 2023
Updated
May 30, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 24, 2023CVE publishedPublication date reported by the CVE source.
  2. May 30, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

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.

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No observations available

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

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

Public exploit references

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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