{"id":"CVE-2026-31786","summary":"Buffer overflow in drivers/xen/sys-hypervisor.c","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nBuffer overflow in drivers/xen/sys-hypervisor.c\n\nThe build id returned by HYPERVISOR_xen_version(XENVER_build_id) is\nneither NUL terminated nor a string.\n\nThe first causes a buffer overflow as sprintf in buildid_show will\nread and copy till it finds a NUL.\n\n00000000  f4 91 51 f4 dd 38 9e 9d  65 47 52 eb 10 71 db 50  |..Q..8..eGR..q.P|\n00000010  b9 a8 01 42 6f 2e 32                              |...Bo.2|\n00000017\n\nSo use a memcpy instead of sprintf to have the correct value:\n\n00000000  f4 91 51 f4 dd 00 9e 9d  65 47 52 eb 10 71 db 50  |..Q.....eGR..q.P|\n00000010  b9 a8 01 42                                       |...B|\n00000014\n\n(the above have a hack to embed a zero inside and check it's\nreturned correctly).\n\nThis is XSA-485 / CVE-2026-31786","modified":"2026-06-18T03:56:13.493639191Z","published":"2026-04-30T10:31:28.293Z","related":["ALSA-2026:24381","ALSA-2026:26427","ALSA-2026:26428","CGA-m53p-86g8-4p77","openSUSE-SU-2026:10703-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31786.json"},"references":[{"type":"WEB","url":"http://www.openwall.com/lists/oss-security/2026/04/28/12"},{"type":"WEB","url":"https://git.kernel.org/stable/c/27fdbab4221b375de54bf91919798d88520c6e28"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4b4defd2fce3f966c25adabf46644a85558f1169"},{"type":"WEB","url":"https://git.kernel.org/stable/c/52cecff98bda2c51eed1c6ce9d21c5d6268fb19d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5c5ff7c7bd15bb536f44b10b3fb5b8408f344d0a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8288d031a01dbacfde3fc643f7be3d23504de64d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d5f59216650c51e5e3fcb7517c825bc8047f60ef"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e3af585e1728c917682b6a3de9a69b41fb9194d4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f458ba102da97fafca106327086fc95f3fc764cb"},{"type":"ADVISORY","url":"http://xenbits.xen.org/xsa/advisory-485.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31786.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31786"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"84b7625728ea311ea35bdaa0eded53c1c56baeaa"},{"fixed":"e3af585e1728c917682b6a3de9a69b41fb9194d4"},{"fixed":"8288d031a01dbacfde3fc643f7be3d23504de64d"},{"fixed":"f458ba102da97fafca106327086fc95f3fc764cb"},{"fixed":"4b4defd2fce3f966c25adabf46644a85558f1169"},{"fixed":"5c5ff7c7bd15bb536f44b10b3fb5b8408f344d0a"},{"fixed":"d5f59216650c51e5e3fcb7517c825bc8047f60ef"},{"fixed":"52cecff98bda2c51eed1c6ce9d21c5d6268fb19d"},{"fixed":"27fdbab4221b375de54bf91919798d88520c6e28"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-31786.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.13.0"},{"fixed":"5.10.254"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.204"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.170"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.137"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.85"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.26"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.3"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-31786.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}