Medium severity · published Jun 21, 2026
CVE-2026-56406
libexpat before 2.8.2 has an integer overflow in XML_ParseBuffer because it lacked a check that was present in XML_Parse
6.9
CVSS
0.2%
EPSS
No
On KEV
Description
libexpat before 2.8.2 has an integer overflow in XML_ParseBuffer because it lacked a check that was present in XML_Parse.
CVSS vector
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
Attack vector
Local
Complexity
High
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 7% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
libexpat · libexpat project
before 2.8.2 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-56406
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-56406
Patch
https://github.com/libexpat/libexpat/pull/1255
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