CVE-2026-56407: Integer Overflow
Published Jun 21, 2026
·Updated
libexpat before 2.8.2 has an integer overflow in doProlog that is related to storeEntityValue and entity textLen.
Affected Software
3 affected componentsFixes available
Expat libexpat<2.8.2
Libexpat Project Libexpat<2.8.2
Microsoft azl3 expat 2.6.4-6<2.8.2-1
2.8.2-1
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 2.8.2-1
Event History
Jun 21, 2026
CVE Published
via MITRE·03:49 PM
Data Sourced
via MITRE·03:49 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·04:16 PM
RemedyDescriptionSeverityWeaknessAffected Software
Jun 27, 2026
Data Sourced
via Microsoft·08:05 AM
DescriptionSeverityWeaknessAffected Software
Updated
via Microsoft·08:05 AM
DescriptionSeverity
Frequently Asked Questions
1
What is the severity of CVE-2026-56407?
The severity of CVE-2026-56407 is rated as medium with a score of 6.9.
2
How do I fix CVE-2026-56407?
To fix CVE-2026-56407, you should upgrade to libexpat version 2.8.2 or later.
3
What vulnerabilities are associated with CVE-2026-56407?
CVE-2026-56407 is associated with an integer overflow vulnerability in the doProlog function of libexpat.
4
What impact does CVE-2026-56407 have on data security?
CVE-2026-56407 can lead to potential data corruption or unauthorized access due to the integer overflow.
5
Which software is affected by CVE-2026-56407?
CVE-2026-56407 affects versions of the Expat library before 2.8.2.