CVE-2026-56411: Integer Overflow
Last updated 24 September 2026
Other sources
xmlwf in libexpat before 2.8.2 has an integer overflow in endDoctypeDecl via NOTATION declarations.
— MITRE
Affected Software
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 - Upgrade
Upgrade
debian/expatto a version that resolves this vulnerability.Fixed in 2.5.0-1+deb12u3Fixed in 2.8.3-1~deb13u1Fixed in 2.8.4-1Fixed in 2.8.4-2 - Upgrade
Upgrade
libexpatto a version that resolves this vulnerability.Fixed in 2.8.2
Event History
Frequently Asked Questions
What is the severity of CVE-2026-56411?
The severity of CVE-2026-56411 is classified as medium with a score of 6.9.
How do I fix CVE-2026-56411?
To fix CVE-2026-56411, upgrade to Expat version 2.8.2 or later.
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.
Which software is affected by CVE-2026-56411?
CVE-2026-56411 affects the Expat library, specifically versions prior to 2.8.2.
When was CVE-2026-56411 published?
CVE-2026-56411 was published on June 21, 2026.