CVE-2026-56406: Integer Overflow
Last updated 24 September 2026
Other sources
libexpat before 2.8.2 has an integer overflow in XMLParseBuffer because it lacked a check that was present in XMLParse.
— 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-2026-56406?
The severity of CVE-2026-56406 is classified as medium with a score of 6.9.
What is CVE-2026-56406 related to in libexpat?
CVE-2026-56406 is related to an integer overflow vulnerability in XML_ParseBuffer in libexpat before version 2.8.2.
How do I fix CVE-2026-56406?
To fix CVE-2026-56406, update libexpat to version 2.8.2 or later.
What is the impact of CVE-2026-56406?
The impact of CVE-2026-56406 includes potential data corruption and denial of service due to the integer overflow.
Which versions of libexpat are affected by CVE-2026-56406?
Versions of libexpat before 2.8.2 are affected by CVE-2026-56406.