CVE-2026-24515

Application crash via omitted encoding-handler context

Published Jan 23, 2026 · Updated Jan 23, 2026

NULL pointer dereference in Expat Project libexpat before 2.7.4 allows local users to crash an application via a crafted external entity. XML_ExternalEntityParserCreate copies the unknown-encoding callback but omits its m_unknownEncodingHandlerData context from the parent parser, leaving the subparser with a NULL pointer. The crash requires applications to use XML_ExternalEntityParserCreate with XML_SetUnknownEncodingHandler and then parse an external entity declaring an unknown encoding.

CVSS severity2.9
Low
EPSS probability0.18%
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 Expat Project libexpat before 2.7.4 allows local users to crash an application via a crafted external entity. XML_ExternalEntityParserCreate copies the unknown-encoding callback but omits its m_unknownEncodingHandlerData context from the parent parser, leaving the subparser with a NULL pointer. The crash requires applications to use XML_ExternalEntityParserCreate with XML_SetUnknownEncodingHandler and then parse an external entity declaring an unknown encoding.

The record

CVE
CVE-2026-24515
Published
Jan 23, 2026
Updated
Jan 23, 2026
Vendor
Expat Project
Product
libexpat
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 23, 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 <2.7.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Expat Project · libexpatversion=0 <2.7.4

Published CVSS scores

2.9MITRECVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
2.5NIST NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/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.

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

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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