xmltok_impl.c in Expat (aka libexpat) before 2.4.5 lacks certain validation of encoding, such as checks for whether a UTF-8 character is valid in a certain context.

References

• https://nvd.nist.gov/vuln/detail/CVE-2022-25235
• libexpat/libexpat#562
• http://www.openwall.com/lists/oss-security/2022/02/19/1
• https://www.debian.org/security/2022/dsa-5085
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3UFRBA3UQVIQKXTBUQXDWQOVWNBKLERU/
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/Y27XO3JMKAOMQZVPS3B4MJGEAHCZF5OM/
• https://security.netapp.com/advisory/ntap-20220303-0008/
• https://lists.debian.org/debian-lts-announce/2022/03/msg00007.html
• https://cert-portal.siemens.com/productcert/pdf/ssa-484086.pdf
• https://www.oracle.com/security-alerts/cpuapr2022.html
• https://security.gentoo.org/glsa/202209-24