CVE-2026-56411: Integer Overflow
Published Jun 21, 2026
·Updated
xmlwf in libexpat before 2.8.2 has an integer overflow in endDoctypeDecl via NOTATION declarations.
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·03:56 PM
Data Sourced
via MITRE·03:56 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·05:16 PM
RemedyDescriptionSeverityWeaknessAffected Software
Jun 27, 2026
Data Sourced
via Microsoft·08:06 AM
DescriptionSeverityWeaknessAffected Software
Updated
via Microsoft·08:06 AM
DescriptionSeverity
Frequently Asked Questions
1
What is the severity of CVE-2026-56411?
The severity of CVE-2026-56411 is classified as medium with a score of 6.9.
2
How do I fix CVE-2026-56411?
To fix CVE-2026-56411, upgrade to Expat version 2.8.2 or later.
3
What type of vulnerability is identified in CVE-2026-56411?
CVE-2026-56411 is an integer overflow vulnerability located in the xmlwf component of libexpat.
4
Which software is affected by CVE-2026-56411?
CVE-2026-56411 affects the Expat library, specifically versions prior to 2.8.2.
5
When was CVE-2026-56411 published?
CVE-2026-56411 was published on June 21, 2026.