{"id":"CVE-2026-72085","revision":null,"records":[{"revision":"4e20facc476c4bc985f7fe441c3c2be8","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-72085","aliases":[],"title":"scsi: xen: scsiback: Free unsubmitted command instead of double-putting it","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nscsi: xen: scsiback: Free unsubmitted command instead of double-putting it\n\nscsiback_get_pend_req() obtains a command tag and returns a vscsibk_pend\nwhose embedded se_cmd has only been memset to 0, so its cmd_kref is 0;\nthe se_cmd is initialised (kref_init() via target_init_cmd()) only\nlater, in scsiback_cmd_exec(), on the successful VSCSIIF_ACT_SCSI_CDB\npath. The two error paths in scsiback_do_cmd_fn() taken before the\ncommand is submitted -- a failed scsiback_gnttab_data_map() and an\nunknown ring_req.act -- call\ntransport_generic_free_cmd(&pending_req->se_cmd, 0), which kref_put()s a\nrefcount of 0. That underflows it (\"refcount_t: underflow;\nuse-after-free\") and, as the release function is not run, leaks the\ncommand tag.\n\nImpact: a pvSCSI guest can leak every command tag of a LUN's session,\nstopping the LUN, by submitting requests with a bad grant reference or\nan unknown request type; under panic_on_warn the refcount underflow\npanics the host.\n\nAdd a helper that just returns the tag with target_free_tag() and sends\nthe error response. It frees the tag while the v2p reference still pins\nthe session, and snapshots the response fields beforehand because\nfreeing the tag can let another ring reuse the pending_req slot.","state":0,"publishedAt":"2026-08-15T05:52:33.521+00:00","modifiedAt":"2026-10-19T21:19:27.216+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"unaffected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"drivers/xen/xen-scsiback.c\"\n ],\n \"versions\": [\n {\n \"version\": \"2dbcdf33dbf61f44b29adb52338282c3d7840d0e\",\n \"lessThan\": \"9c0f6894982b1f13bda220707497b25ac9c95bdb\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"2dbcdf33dbf61f44b29adb52338282c3d7840d0e\",\n \"lessThan\": \"a13b789497a7fdd27d4d63f5c69d23db706ef0fe\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"2dbcdf33dbf61f44b29adb52338282c3d7840d0e\",\n \"lessThan\": \"fa588f28401102652068c4cc75e135507f4b5106\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"2dbcdf33dbf61f44b29adb52338282c3d7840d0e\",\n \"lessThan\": \"fcd64d4d97af5d9736f31040f8ed8cd4c17e4c45\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"2dbcdf33dbf61f44b29adb52338282c3d7840d0e\",\n \"lessThan\": \"f1516c56ac540da1769f264c3cfefe4499548a5d\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"2dbcdf33dbf61f44b29adb52338282c3d7840d0e\",\n \"lessThan\": \"1e97c404e44991fb087c38ccd7414f2d326f9b74\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"2dbcdf33dbf61f44b29adb52338282c3d7840d0e\",\n \"lessThan\": \"ca978f8a93d4d36841839bf2847d29b88c2591d6\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n }\n ]\n }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"affected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"drivers/xen/xen-scsiback.c\"\n ],\n \"versions\": [\n {\n \"version\": \"4.6\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"4.6\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.15.212\",\n \"lessThanOrEqual\": \"5.15.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.1.178\",\n \"lessThanOrEqual\": \"6.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.145\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.97\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.18.40\",\n \"lessThanOrEqual\": \"6.18.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.1.5\",\n \"lessThanOrEqual\": \"7.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.2\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","score":9.3,"severity":"CRITICAL"}],"references":["https://git.kernel.org/stable/c/9c0f6894982b1f13bda220707497b25ac9c95bdb","https://git.kernel.org/stable/c/a13b789497a7fdd27d4d63f5c69d23db706ef0fe","https://git.kernel.org/stable/c/fa588f28401102652068c4cc75e135507f4b5106","https://git.kernel.org/stable/c/fcd64d4d97af5d9736f31040f8ed8cd4c17e4c45","https://git.kernel.org/stable/c/f1516c56ac540da1769f264c3cfefe4499548a5d","https://git.kernel.org/stable/c/1e97c404e44991fb087c38ccd7414f2d326f9b74","https://git.kernel.org/stable/c/ca978f8a93d4d36841839bf2847d29b88c2591d6"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72085","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-72085","identifiers":["CVE-2026-72085"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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Not a global EUVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-383c643166b94ac4b6a615647191978e","complete":true,"records":13654,"lastAttemptAt":"2026-11-08T15:12:52.0979565+00:00","lastSuccessAt":"2026-11-08T13:04:50.073+00:00","error":null,"lastVerifiedAt":"2026-11-08T13:04:50.073+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13706,"expectedIdentifiers":13706,"failedIdentifiers":0},{"source":"first-epss:nuget","scope":"FIRST EPSS for explicit CVE aliases in the collected public NuGet archive. Not a global EPSS backfill.","generation":"2026-11-08T15:12:21.7721538+00:00","complete":true,"records":1096,"lastAttemptAt":"2026-11-08T15:12:21.7721538+00:00","lastSuccessAt":"2026-11-08T15:12:25.6162622+00:00","error":null,"lastVerifiedAt":"2026-11-08T15:12:25.6162636+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"nvd","scope":"Rolling NVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global NVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. 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