CVE-2022-40304Public exploit

Crash or code execution via cyclic entities

Published Nov 23, 2022 · Updated Apr 28, 2025

Double free in XMLsoft libxml2 before 2.10.3 allows context-dependent attackers to crash a process or execute code through crafted XML. During entity-cycle cleanup, libxml2 clears the first byte of dictionary-backed entity content, corrupting the dictionary's hash-table key and enabling a later double free. An application must parse attacker-supplied XML containing a reference cycle; the resulting memory corruption can terminate the process or enable code execution.

CVSS severity7.8
High
EPSS probability6.78%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Double free in XMLsoft libxml2 before 2.10.3 allows context-dependent attackers to crash a process or execute code through crafted XML. During entity-cycle cleanup, libxml2 clears the first byte of dictionary-backed entity content, corrupting the dictionary's hash-table key and enabling a later double free. An application must parse attacker-supplied XML containing a reference cycle; the resulting memory corruption can terminate the process or enable code execution.

The record

CVE
CVE-2022-40304
Published
Nov 23, 2022
Updated
Apr 28, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-415, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 23, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 28, 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 vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.8Oracle LinuxCVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
7.8Canonical UbuntuCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.2Amazon LinuxCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-415Double Free
T1203Exploitation for Client Execution

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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