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Vulnerability · Published Jun 21, 2026 · Assigned by mitre

CVE-2026-56405

Medium 6.9

In plain English

A medium-severity integer overflow in libexpat from libexpat project. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.9Medium
Exploit odds (30 days)0.1%top 97.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

libexpat before 2.8.2 has an integer overflow in getAttributeId.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.21expat2.8.2-r0ALPINE-CVE-2026-56405
Alpine:v3.22expat2.8.2-r0ALPINE-CVE-2026-56405
Alpine:v3.23expat2.8.2-r0ALPINE-CVE-2026-56405
Alpine:v3.24expat2.8.2-r0ALPINE-CVE-2026-56405
Debian:12expat2.5.0-1+deb12u3DEBIAN-CVE-2026-56405
Debian:13expat2.8.2-1~deb13u1DEBIAN-CVE-2026-56405
Debian:14expat2.8.2-1DEBIAN-CVE-2026-56405
Ubuntu:22.04:LTScadaverno fix listedUBUNTU-CVE-2026-56405
Ubuntu:24.04:LTScadaverno fix listedUBUNTU-CVE-2026-56405
Ubuntu:25.10cadaverno fix listedUBUNTU-CVE-2026-56405
Ubuntu:26.04:LTScadaverno fix listedUBUNTU-CVE-2026-56405
Ubuntu:26.10cadaverno fix listedUBUNTU-CVE-2026-56405
Ubuntu:22.04:LTSexpat2.4.7-1ubuntu0.8UBUNTU-CVE-2026-56405
Ubuntu:22.04:LTSexpat2.4.7-1ubuntu0.8USN-8790-1
Ubuntu:24.04:LTSexpat2.6.1-2ubuntu0.5UBUNTU-CVE-2026-56405
Ubuntu:24.04:LTSexpat2.6.1-2ubuntu0.5USN-8790-1
Ubuntu:25.10expatno fix listedUBUNTU-CVE-2026-56405
Ubuntu:26.04:LTSexpat2.7.4-1ubuntu0.1UBUNTU-CVE-2026-56405
Ubuntu:26.04:LTSexpat2.7.4-1ubuntu0.1USN-8790-1
Ubuntu:22.04:LTSinsighttoolkit4no fix listedUBUNTU-CVE-2026-56405
Ubuntu:22.04:LTSmatanzano fix listedUBUNTU-CVE-2026-56405
Ubuntu:24.04:LTSmatanzano fix listedUBUNTU-CVE-2026-56405
Ubuntu:25.10matanzano fix listedUBUNTU-CVE-2026-56405
Ubuntu:26.04:LTSmatanzano fix listedUBUNTU-CVE-2026-56405
Ubuntu:26.10matanzano fix listedUBUNTU-CVE-2026-56405
Ubuntu:25.10swish-eno fix listedUBUNTU-CVE-2026-56405
Ubuntu:26.10swish-eno fix listedUBUNTU-CVE-2026-56405
Ubuntu:22.04:LTStdomno fix listedUBUNTU-CVE-2026-56405
Ubuntu:24.04:LTStdomno fix listedUBUNTU-CVE-2026-56405
Ubuntu:25.10tdomno fix listedUBUNTU-CVE-2026-56405
Ubuntu:26.04:LTStdomno fix listedUBUNTU-CVE-2026-56405
Ubuntu:26.10tdomno fix listedUBUNTU-CVE-2026-56405
Ubuntu:22.04:LTSwbxml2no fix listedUBUNTU-CVE-2026-56405
Ubuntu:24.04:LTSwbxml2no fix listedUBUNTU-CVE-2026-56405
Ubuntu:25.10wbxml2no fix listedUBUNTU-CVE-2026-56405
Ubuntu:26.04:LTSwbxml2no fix listedUBUNTU-CVE-2026-56405
Ubuntu:26.10wbxml2no fix listedUBUNTU-CVE-2026-56405
Ubuntu:25.10xmlrpc-cno fix listedUBUNTU-CVE-2026-56405
Ubuntu:26.04:LTSxmlrpc-cno fix listedUBUNTU-CVE-2026-56405
Ubuntu:26.10xmlrpc-cno fix listedUBUNTU-CVE-2026-56405

Affected products (as reported)

VendorProductVersions
libexpat project libexpat 0 – before 2.8.2

Weakness: CWE-190 · Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L

References