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libexpat EUVDEUVD-2026-38185

| CVE-2026-56408 MEDIUM
Integer Overflow or Wraparound (CWE-190)
2026-06-21 mitre GHSA-9jq5-63hm-6q5g
Integer Overflow Buffer Overflow Libexpat Suse
6.9
CVSS 3.1 · Vendor: mitre
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Severity by source

Vendor (mitre) PRIMARY
6.9 MEDIUM
AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
vuln.today AI
7.7 HIGH

AV:N because libexpat typically processes untrusted network-sourced XML; AC:H because reliable heap overflow exploitation requires precise heap layout control.

3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
4.0 AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N
SUSE
MEDIUM
qualitative

Primary rating from Vendor (mitre).

CVSS VectorVendor: mitre

CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
Attack Vector
Local
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
Low

Lifecycle Timeline

3
Source Code Evidence Fetched
Jun 22, 2026 - 06:42 vuln.today
Analysis Generated
Jun 22, 2026 - 06:42 vuln.today
Patch available
Jun 21, 2026 - 17:01 EUVD

DescriptionCVE.org

libexpat before 2.8.2 has an integer overflow in copyString.

AnalysisAI

Integer overflow in libexpat's copyString function (xmlparse.c) allows heap buffer overflow when processing specially crafted XML input, affecting all libexpat versions before 2.8.2. The missing bounds check on a size multiplication permits an attacker-controlled string length to wrap around SIZE_MAX, producing an undersized heap allocation that is subsequently overwritten - enabling potential memory corruption, arbitrary code execution, or data disclosure in any application consuming the library. …

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Recon
Craft XML with oversized string value
Delivery
Submit XML to libexpat-consuming application
Exploit
copyString multiplies charsRequired past SIZE_MAX
Install
Undersized heap buffer allocated
C2
String write overflows into adjacent heap
Execute
Heap metadata or pointer corruption achieved
Impact
Arbitrary code execution in application context
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Vulnerability AssessmentAI

Exploitation The vulnerability is triggered by any XML input containing a string whose length causes charsRequired * sizeof(XML_Char) to overflow SIZE_MAX in the copyString function. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment The NVD-assigned CVSS 3.1 score of 6.9 (AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L) reflects high exploitation complexity and a local attack vector - the latter being conservative for a parsing library that routinely handles XML from network-sourced input. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario An attacker submits a malicious XML document containing a string element whose character count is engineered to overflow SIZE_MAX when multiplied by sizeof(XML_Char) inside copyString. The resulting malloc call allocates a buffer far smaller than needed, and the subsequent string copy overwrites adjacent heap memory. …
Remediation The primary fix is to upgrade libexpat to version 2.8.2 or later, which incorporates the integer overflow guard added in upstream commit 16e2efd867ea8567ffa012210b52ef5918e20817 (https://github.com/libexpat/libexpat/commit/16e2efd867ea8567ffa012210b52ef5918e20817). … Detailed patch versions, workarounds, and compensating controls in full report.
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Same weakness CWE-190 – Integer Overflow or Wraparound

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7.5
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CVE-2016-1010 HIGH
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CVE-2013-3940 CRITICAL
9.3

Same technique Integer Overflow

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CVE-2014-0497 CRITICAL POC
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CVE-2015-8651 HIGH
8.8
CVE-2012-5054 HIGH POC
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CVE-2014-0569 CRITICAL POC
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Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
SLES15-SP5-CHOST-BYOS-SAP-CCloud Not-Affected
SLES15-SP5-CHOST-BYOS-SAP-CCloud Affected
SLES15-SP6-CHOST-BYOS Affected
SLES15-SP6-CHOST-BYOS-Aliyun Affected
SLES15-SP6-CHOST-BYOS-Azure Affected

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EUVD-2026-38185 vulnerability details – vuln.today
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