{"id":"ALPINE-CVE-2019-18423","details":"An issue was discovered in Xen through 4.12.x allowing ARM guest OS users to cause a denial of service via a XENMEM_add_to_physmap hypercall. p2m-\u003emax_mapped_gfn is used by the functions p2m_resolve_translation_fault() and p2m_get_entry() to sanity check guest physical frame. The rest of the code in the two functions will assume that there is a valid root table and check that with BUG_ON(). The function p2m_get_root_pointer() will ignore the unused top bits of a guest physical frame. This means that the function p2m_set_entry() will alias the frame. However, p2m-\u003emax_mapped_gfn will be updated using the original frame. It would be possible to set p2m-\u003emax_mapped_gfn high enough to cover a frame that would lead p2m_get_root_pointer() to return NULL in p2m_get_entry() and p2m_resolve_translation_fault(). Additionally, the sanity check on p2m-\u003emax_mapped_gfn is off-by-one allowing \"highest mapped + 1\" to be considered valid. However, p2m_get_root_pointer() will return NULL. The problem could be triggered with a specially crafted hypercall XENMEM_add_to_physmap{, _batch} followed by an access to an address (via hypercall or direct access) that passes the sanity check but cause p2m_get_root_pointer() to return NULL. A malicious guest administrator may cause a hypervisor crash, resulting in a Denial of Service (DoS). Xen version 4.8 and newer are vulnerable. Only Arm systems are vulnerable. x86 systems are not affected.","modified":"2026-09-10T06:17:54.518735107Z","published":"2019-10-31T14:15:11.137Z","upstream":["CVE-2019-18423"],"references":[{"type":"ADVISORY","url":"https://security.alpinelinux.org/vuln/CVE-2019-18423"}],"affected":[{"package":{"name":"xen","ecosystem":"Alpine:v3.10","purl":"pkg:apk/alpine/xen?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.8"},{"fixed":"4.12.1-r1"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2019-18423.json"}},{"package":{"name":"xen","ecosystem":"Alpine:v3.11","purl":"pkg:apk/alpine/xen?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.8"},{"fixed":"4.13.0-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2019-18423.json"}},{"package":{"name":"xen","ecosystem":"Alpine:v3.12","purl":"pkg:apk/alpine/xen?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.8"},{"fixed":"4.13.0-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2019-18423.json"}},{"package":{"name":"xen","ecosystem":"Alpine:v3.13","purl":"pkg:apk/alpine/xen?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.8"},{"fixed":"4.13.0-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2019-18423.json"}},{"package":{"name":"xen","ecosystem":"Alpine:v3.14","purl":"pkg:apk/alpine/xen?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.8"},{"fixed":"4.13.0-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2019-18423.json"}},{"package":{"name":"xen","ecosystem":"Alpine:v3.15","purl":"pkg:apk/alpine/xen?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.8"},{"fixed":"4.13.0-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2019-18423.json"}},{"package":{"name":"xen","ecosystem":"Alpine:v3.16","purl":"pkg:apk/alpine/xen?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.8"},{"fixed":"4.13.0-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2019-18423.json"}},{"package":{"name":"xen","ecosystem":"Alpine:v3.17","purl":"pkg:apk/alpine/xen?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.8"},{"fixed":"4.13.0-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2019-18423.json"}},{"package":{"name":"xen","ecosystem":"Alpine:v3.18","purl":"pkg:apk/alpine/xen?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.8"},{"fixed":"4.13.0-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2019-18423.json"}},{"package":{"name":"xen","ecosystem":"Alpine:v3.19","purl":"pkg:apk/alpine/xen?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.8"},{"fixed":"4.13.0-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2019-18423.json"}},{"package":{"name":"xen","ecosystem":"Alpine:v3.20","purl":"pkg:apk/alpine/xen?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.8"},{"fixed":"4.13.0-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2019-18423.json"}},{"package":{"name":"xen","ecosystem":"Alpine:v3.21","purl":"pkg:apk/alpine/xen?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.8"},{"fixed":"4.13.0-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2019-18423.json"}},{"package":{"name":"xen","ecosystem":"Alpine:v3.22","purl":"pkg:apk/alpine/xen?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.8"},{"fixed":"4.13.0-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2019-18423.json"}},{"package":{"name":"xen","ecosystem":"Alpine:v3.23","purl":"pkg:apk/alpine/xen?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.8"},{"fixed":"4.13.0-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2019-18423.json"}},{"package":{"name":"xen","ecosystem":"Alpine:v3.24","purl":"pkg:apk/alpine/xen?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.8"},{"fixed":"4.13.0-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-c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