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Libexpat CVE-2026-25210

MEDIUM
Integer Overflow or Wraparound (CWE-190)
2026-01-30 cve@mitre.org
Buffer Overflow Integer Overflow Libexpat Libexpat Project
6.9
CVSS 3.1 · NVD
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Vulnerability Assessment

Weakness
CWE
CWE-190
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V15 - Secure Coding and Architecture Integer overflow checks
MITRE ATT&CK

1 technique across 1 tactic: Execution

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

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Impact

CVSS 6.9 (MEDIUM). Attack vector: Local. Complexity: High. Privileges required: None. User interaction: None.
Exploit ScenarioDerived

An attacker could exploit this vulnerability to compromise the affected system.
This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

Libexpat versions before 2.7.4 are vulnerable to integer overflow in the doContent function during tag buffer reallocation, enabling local attackers with no privileges to achieve high-impact confidentiality and integrity violations. The flaw stems from missing overflow validation when calculating buffer sizes, allowing memory corruption that could lead to information disclosure or code execution. A patch is available for affected systems.

Earlier versions of this analysis (1)
v1 Mar 12, 2026 - 22:00 CVSS 6.9

In libexpat before 2.7.4, the doContent function does not properly determine the buffer size bufSize because there is no integer overflow check for tag buffer reallocation. [CVSS 6.9 MEDIUM]

RemediationAI

A vendor patch is available — apply it immediately.

Affects your stack

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Technical ContextAI · show details

Classified as CWE-190 (Integer Overflow or Wraparound). Affects Libexpat. In libexpat before 2.7.4, the doContent function does not properly determine the buffer size bufSize because there is no integer overflow check for tag buffer reallocation.

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  • Exploit and PoC references, threat intelligence from 22 sources
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Severity by source

NVD PRIMARY 6.9 MEDIUM
AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
SUSE MEDIUM
Red Hat 6.9 MEDIUM

Primary rating from NVD.

CVSS VectorNVD

Attack Vector
Local
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
Low

Lifecycle Timeline

2
Patch released
Mar 10, 2026 - 18:17 nvd
Patch available
CVE Published
Jan 30, 2026 - 07:16 nvd
MEDIUM 6.9

DescriptionCVE.org

In libexpat before 2.7.4, the doContent function does not properly determine the buffer size bufSize because there is no integer overflow check for tag buffer reallocation.

Executive ViewAI

Why It Matters

Organizations using libexpat should be aware of notable risk from CVE-2026-25210, a integer overflow vulnerability rated CVSS 6.9. Exploitation could cause memory corruption or application crashes. A patch is available and should be applied during regular vulnerability management.

Business Impact: Moderate
Compensating Controls

Apply vendor patch. If patching is delayed: enable ASLR/DEP, apply network segmentation.

Threat Intelligence Overview

EPSS Score
0.0%
Top 100% exploitable
Threat Intel
2
1 source
Data Quality
5 sources
Confidence: Medium
NVD CVE.org EPSS CISA Vendor GitHub

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.0%
Patch available Yes
Active threat Yes
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

Exploitation· derived
None
System Exposure· derived
Small
Automatable· derived
No

Priority Score

44
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +34
PoC: 0
Weaponized: 0
Threat intel: +10
Gov advisory: 0

Attack Technique

Buffer Overflow HIGH

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

Integer Overflow MEDIUM

Integer overflow occurs when an arithmetic operation produces a result that exceeds the maximum value a given integer type can store.

Affected Products (CPE)CVE.org

cpe:2.3:a:libexpat_project:libexpat:*:*:*:*:*:*:*:*

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expat before version 2.4.0 does not properly handle entities expansion unless an application developer uses the XML_SetE
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Same weakness CWE-190 – Integer Overflow or Wraparound

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9.8
CVE-2017-3599 HIGH POC
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CVE-2026-97229 CRITICAL POC
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CVE-2017-7529 HIGH
7.5

Same technique Buffer Overflow

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CVE-2009-0927 HIGH POC
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CVE-2012-1889 HIGH POC
8.8

Vendor StatusVendor

SUSE

Severity: Medium
Product Status
Container private-registry/harbor-portal:1.1.1-1.31 Container private-registry/harbor-trivy-adapter:1.1.1-1.32 Image SLES15-SP7-CHOST-BYOS-Aliyun Image SLES15-SP7-CHOST-BYOS-Azure Image SLES15-SP7-CHOST-BYOS-EC2 Image SLES15-SP7-CHOST-BYOS-GCE Image SLES15-SP7-CHOST-BYOS-GDC Image SLES15-SP7-CHOST-BYOS-SAP-CCloud Image SLES15-SP7-GCE-3P Image pr_15_7 Image proxy-httpd-image Image proxy-salt-broker-image Image proxy-squid-image Image proxy-ssh-image Image proxy-tftpd-image Image server-database-migration-image Image server-hub-xmlrpc-api-image Image server-image Image server-saline-image Affected
Container suse/ltss/sle12.5/sles12sp5:8.5.201 Affected
Container suse/manager/4.3/proxy-httpd:4.3.16.2.9.73.20 Container suse/manager/4.3/proxy-salt-broker:4.3.16.2.9.63.21 Container suse/manager/4.3/proxy-ssh:4.3.16.2.9.63.14 Container suse/manager/4.3/proxy-tftpd:4.3.16.2.9.63.15 Container suse/manager/5.0/x86_64/proxy-httpd:latest Container suse/manager/5.0/x86_64/proxy-salt-broker:latest Container suse/manager/5.0/x86_64/proxy-ssh:latest Container suse/manager/5.0/x86_64/proxy-tftpd:latest Container suse/manager/5.0/x86_64/server-hub-xmlrpc-api:latest Container suse/manager/5.0/x86_64/server-migration-14-16:latest Container suse/manager/5.0/x86_64/server:latest Container suse/sle-micro/base-5.5:2.0.4-5.8.249 Container suse/sle-micro/kvm-5.5:2.0.4-3.5.478 Image SLES15-SP4-HPC-BYOS Image SLES15-SP4-HPC-BYOS-EC2 Image SLES15-SP4-HPC-EC2 Image SLES15-SP4-Hardened-BYOS Image SLES15-SP4-Hardened-BYOS-EC2 Image SLES15-SP5-HPC-BYOS-EC2 Image SLES15-SP5-Hardened-BYOS-EC2 Image SLES15-SP5-Micro-5-5 Image SLES15-SP5-Micro-5-5-Azure Affected
Container suse/sl-micro/6.0/baremetal-os-container:2.1.3-6.123 Affected
Container suse/sl-micro/6.0/base-os-container:2.1.3-7.92 Container suse/sl-micro/6.0/kvm-os-container:2.1.3-6.110 Container suse/sl-micro/6.0/rt-os-container:2.1.3-7.124 Container suse/sl-micro/6.0/toolbox:13.2-9.65 Container suse/sl-micro/6.1/baremetal-os-container:2.2.1-7.2 Container suse/sl-micro/6.1/base-os-container:2.2.1-5.78 Container suse/sl-micro/6.1/kvm-os-container:2.2.1-5.80 Container suse/sl-micro/6.1/rt-os-container:2.2.1-5.71 Image SL-Micro Image SL-Micro-Azure Image SL-Micro-BYOS-Azure Image SL-Micro-BYOS-EC2 Image SL-Micro-BYOS-GCE Image SL-Micro-EC2 Image SLE-Micro Image SLE-Micro-Azure Image SLE-Micro-BYOS Image SLE-Micro-BYOS-Azure Image SLE-Micro-BYOS-EC2 Image SLE-Micro-BYOS-GCE Image SLE-Micro-EC2 Image SLE-Micro-GCE Image SUSE-Multi-Linux-Manager-Proxy-BYOS-Azure Image SUSE-Multi-Linux-Manager-Proxy-BYOS-EC2 Image SUSE-Multi-Linux-Manager-Proxy-BYOS-GCE Image SUSE-Multi-Linux-Manager-Server-Azure-llc Image SUSE-Multi-Linux-Manager-Server-Azure-ltd Image SUSE-Multi-Linux-Manager-Server-BYOS-Azure Image SUSE-Multi-Linux-Manager-Server-BYOS-EC2 Image SUSE-Multi-Linux-Manager-Server-BYOS-GCE Image SUSE-Multi-Linux-Manager-Server-EC2-llc Image SUSE-Multi-Linux-Manager-Server-EC2-ltd Affected

Threat IntelligenceMISP

CISA Advisories
ICSA-26-155-04 ICSA-26-188-05
Sources: CISA (public domain)

References

Advisories & patches
PATCH https://github.com/libexpat/libexpat/pull/1075 PATCH https://github.com/libexpat/libexpat/pull/1075/commits/9c2d990389e6abe2e44527eeaa8b39f16fe859c7 ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:0386/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:0646/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:0647/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:0826/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:20350/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:20481/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:20627/ ADVISORY https://www.suse.com/support/update/SUSE-SU-2026:20642/ REF https://cert-portal.siemens.com/productcert/html/ssa-253495.html

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