CVE-2024-56171

Memory corruption via stale identity-constraint array pointer

Published Feb 18, 2025 · Updated Nov 3, 2025

Use-after-free in XML Schema validation in XMLSoft libxml2 before 2.12.10 and 2.13.0 through 2.13.5 allows attackers to corrupt memory. In xmlSchemaIDCFillNodeTables and xmlSchemaBubbleIDCNodeTables, xmlSchemaItemListAdd can reallocate the items array while a local dupls pointer still references the old allocation. Exploitation requires validation of a crafted XML document against a schema with identity constraints, or use of a crafted XML schema.

CVSS severity7.8
High
EPSS probability1.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in XML Schema validation in XMLSoft libxml2 before 2.12.10 and 2.13.0 through 2.13.5 allows attackers to corrupt memory. In xmlSchemaIDCFillNodeTables and xmlSchemaBubbleIDCNodeTables, xmlSchemaItemListAdd can reallocate the items array while a local dupls pointer still references the old allocation. Exploitation requires validation of a crafted XML document against a schema with identity constraints, or use of a crafted XML schema.

The record

CVE
CVE-2024-56171
Published
Feb 18, 2025
Updated
Nov 3, 2025
Vendor
XMLSoft
Product
libxml2
Classifications
CWE-416
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 18, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <2.12.10
  2. Affected versionversion=2.13.0 <2.13.6

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

XMLSoft · libxml2version=0 <2.12.10; version=2.13.0 <2.13.6

Published CVSS scores

7.8Canonical UbuntuCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free

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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