CVE-2026-56409: Integer Overflow
Last updated 24 September 2026
Other sources
xmlwf in libexpat before 2.8.2 has an integer overflow for the output filename when -d outputDir is used.
— 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-2026-56409?
The severity of CVE-2026-56409 is medium, rated at 6.5.
What kind of vulnerability is CVE-2026-56409?
CVE-2026-56409 is classified as an integer overflow vulnerability.
How does CVE-2026-56409 affect software?
CVE-2026-56409 affects the Expat library's xmlwf tool when it is used with the -d outputDir option.
How do I fix CVE-2026-56409?
To fix CVE-2026-56409, upgrade to libexpat version 2.8.2 or later.
What can be the consequences of exploiting CVE-2026-56409?
Exploiting CVE-2026-56409 may lead to potential denial of service or disclosure of sensitive information.