Skip to main content

libexpat CVE-2026-56408

| EUVDEUVD-2026-38185 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
Share

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. …

Unlock full vulnerability intelligence

  • Risk assessment & exploitation conditions
  • Attack chain visualization
  • Remediation with exact patch versions
  • Threat intelligence from 22 sources
  • Personal watchlist & email alerts
Continue with Google Continue with GitHub

Free forever · No credit card required

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
Sign in to reveal

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.
Sign in to read full assessment

Threat intelligence, references, and detailed analysis are available after sign-in.

More in Libexpat

View all
CVE-2022-25315 CRITICAL POC
9.8 Feb 18

In Expat (aka libexpat) before 2.4.5, there is an integer overflow in storeRawNames. Rated critical severity (CVSS 9.8),
CVE-2017-9233 HIGH POC
7.5 Jul 25

XML External Entity vulnerability in libexpat 2.2.0 and earlier (Expat XML Parser Library) allows attackers to put the p
CVE-2026-45186 HIGH POC
7.5 May 10

Denial of service in libexpat before 2.8.1 lets remote attackers exhaust CPU by submitting moderately sized crafted XML

CVE-2022-43680 HIGH POC
7.5 Oct 24

In libexpat through 2.4.9, there is a use-after free caused by overeager destruction of a shared DTD in XML_ExternalEnti
CVE-2019-15903 HIGH POC
7.5 Sep 04

In libexpat before 2.2.8, crafted XML input could fool the parser into changing from DTD parsing to document parsing too
CVE-2013-0340 MEDIUM POC
6.8 Jan 21

expat before version 2.4.0 does not properly handle entities expansion unless an application developer uses the XML_SetE
CVE-2016-0718 CRITICAL
9.8 May 26

Expat allows context-dependent attackers to cause a denial of service (crash) or possibly execute arbitrary code via a m
CVE-2024-45492 CRITICAL
9.8 Aug 30

An issue was discovered in libexpat before 2.6.3. Rated critical severity (CVSS 9.8), this vulnerability is remotely exp
CVE-2024-45491 CRITICAL
9.8 Aug 30

An issue was discovered in libexpat before 2.6.3. Rated critical severity (CVSS 9.8), this vulnerability is remotely exp
CVE-2016-4472 HIGH
8.1 Jun 30

The overflow protection in Expat is removed by compilers with certain optimization settings, which allows remote attacke
CVE-2022-40674 HIGH
8.1 Sep 14

libexpat before 2.4.9 has a use-after-free in the doContent function in xmlparse.c. Rated high severity (CVSS 8.1), this
CVE-2016-5300 HIGH
7.5 Jun 16

The XML parser in Expat does not use sufficient entropy for hash initialization, which allows context-dependent attacker

Same weakness CWE-190 – Integer Overflow or Wraparound

View all
CVE-2013-2729 CRITICAL POC
9.8
CVE-2015-8651 HIGH
8.8
CVE-2012-5054 HIGH POC
8.8
CVE-2014-0569 CRITICAL POC
9.3
CVE-2017-3599 HIGH POC
7.5
CVE-2017-7529 HIGH
7.5
CVE-2016-1010 HIGH
8.8
CVE-2013-3940 CRITICAL
9.3

Same technique Integer Overflow

View all
CVE-2014-0497 CRITICAL POC
9.8
CVE-2013-2729 CRITICAL POC
9.8
CVE-2015-8651 HIGH
8.8
CVE-2012-5054 HIGH POC
8.8
CVE-2014-0569 CRITICAL POC
9.3
CVE-2017-3599 HIGH POC
7.5
CVE-2017-7529 HIGH
7.5
CVE-2016-1010 HIGH
8.8

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

Share

CVE-2026-56408 vulnerability details – vuln.today
Back

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy