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Vulnerability · Published Jun 21, 2026 · Assigned by mitre

CVE-2026-56407

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 0.2% (higher than 7% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.9Medium
Exploit odds (30 days)0.2%top 93.1% 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 doProlog that is related to storeEntityValue and entity textLen.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.21expat2.8.2-r0ALPINE-CVE-2026-56407
Alpine:v3.22expat2.8.2-r0ALPINE-CVE-2026-56407
Alpine:v3.23expat2.8.2-r0ALPINE-CVE-2026-56407
Alpine:v3.24expat2.8.2-r0ALPINE-CVE-2026-56407
Debian:12expat2.5.0-1+deb12u3DEBIAN-CVE-2026-56407
Debian:13expat2.8.2-1~deb13u1DEBIAN-CVE-2026-56407
Debian:14expat2.8.2-1DEBIAN-CVE-2026-56407
Ubuntu:22.04:LTScadaverno fix listedUBUNTU-CVE-2026-56407
Ubuntu:24.04:LTScadaverno fix listedUBUNTU-CVE-2026-56407
Ubuntu:25.10cadaverno fix listedUBUNTU-CVE-2026-56407
Ubuntu:26.04:LTScadaverno fix listedUBUNTU-CVE-2026-56407
Ubuntu:26.10cadaverno fix listedUBUNTU-CVE-2026-56407
Ubuntu:22.04:LTSexpat2.4.7-1ubuntu0.9UBUNTU-CVE-2026-56407
Ubuntu:22.04:LTSexpat2.4.7-1ubuntu0.9USN-8813-1
Ubuntu:24.04:LTSexpat2.6.1-2ubuntu0.6UBUNTU-CVE-2026-56407
Ubuntu:24.04:LTSexpat2.6.1-2ubuntu0.6USN-8813-1
Ubuntu:25.10expatno fix listedUBUNTU-CVE-2026-56407
Ubuntu:26.04:LTSexpat2.7.4-1ubuntu0.2UBUNTU-CVE-2026-56407
Ubuntu:26.04:LTSexpat2.7.4-1ubuntu0.2USN-8813-1
Ubuntu:22.04:LTSinsighttoolkit4no fix listedUBUNTU-CVE-2026-56407
Ubuntu:22.04:LTSmatanzano fix listedUBUNTU-CVE-2026-56407
Ubuntu:24.04:LTSmatanzano fix listedUBUNTU-CVE-2026-56407
Ubuntu:25.10matanzano fix listedUBUNTU-CVE-2026-56407
Ubuntu:26.04:LTSmatanzano fix listedUBUNTU-CVE-2026-56407
Ubuntu:26.10matanzano fix listedUBUNTU-CVE-2026-56407
Ubuntu:25.10swish-eno fix listedUBUNTU-CVE-2026-56407
Ubuntu:26.10swish-eno fix listedUBUNTU-CVE-2026-56407
Ubuntu:22.04:LTStdomno fix listedUBUNTU-CVE-2026-56407
Ubuntu:24.04:LTStdomno fix listedUBUNTU-CVE-2026-56407
Ubuntu:25.10tdomno fix listedUBUNTU-CVE-2026-56407
Ubuntu:26.04:LTStdomno fix listedUBUNTU-CVE-2026-56407
Ubuntu:26.10tdomno fix listedUBUNTU-CVE-2026-56407
Ubuntu:22.04:LTSwbxml2no fix listedUBUNTU-CVE-2026-56407
Ubuntu:24.04:LTSwbxml2no fix listedUBUNTU-CVE-2026-56407
Ubuntu:25.10wbxml2no fix listedUBUNTU-CVE-2026-56407
Ubuntu:26.04:LTSwbxml2no fix listedUBUNTU-CVE-2026-56407
Ubuntu:26.10wbxml2no fix listedUBUNTU-CVE-2026-56407
Ubuntu:25.10xmlrpc-cno fix listedUBUNTU-CVE-2026-56407
Ubuntu:26.04:LTSxmlrpc-cno fix listedUBUNTU-CVE-2026-56407
Ubuntu:26.10xmlrpc-cno fix listedUBUNTU-CVE-2026-56407

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