{"api_version":"1","generated_at":"2026-08-15T10:15:04+00:00","cve":"CVE-2026-72085","urls":{"html":"https://cve.report/CVE-2026-72085","api":"https://cve.report/api/cve/CVE-2026-72085.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-72085","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-72085"},"summary":{"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":"PUBLISHED","assigner":"Linux","published_at":"2026-08-15 06:21:22","updated_at":"2026-08-15 06:21:22"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/1e97c404e44991fb087c38ccd7414f2d326f9b74","name":"https://git.kernel.org/stable/c/1e97c404e44991fb087c38ccd7414f2d326f9b74","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/fa588f28401102652068c4cc75e135507f4b5106","name":"https://git.kernel.org/stable/c/fa588f28401102652068c4cc75e135507f4b5106","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a13b789497a7fdd27d4d63f5c69d23db706ef0fe","name":"https://git.kernel.org/stable/c/a13b789497a7fdd27d4d63f5c69d23db706ef0fe","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9c0f6894982b1f13bda220707497b25ac9c95bdb","name":"https://git.kernel.org/stable/c/9c0f6894982b1f13bda220707497b25ac9c95bdb","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f1516c56ac540da1769f264c3cfefe4499548a5d","name":"https://git.kernel.org/stable/c/f1516c56ac540da1769f264c3cfefe4499548a5d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/ca978f8a93d4d36841839bf2847d29b88c2591d6","name":"https://git.kernel.org/stable/c/ca978f8a93d4d36841839bf2847d29b88c2591d6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/fcd64d4d97af5d9736f31040f8ed8cd4c17e4c45","name":"https://git.kernel.org/stable/c/fcd64d4d97af5d9736f31040f8ed8cd4c17e4c45","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-72085","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72085","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2dbcdf33dbf61f44b29adb52338282c3d7840d0e 9c0f6894982b1f13bda220707497b25ac9c95bdb git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2dbcdf33dbf61f44b29adb52338282c3d7840d0e a13b789497a7fdd27d4d63f5c69d23db706ef0fe git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2dbcdf33dbf61f44b29adb52338282c3d7840d0e fa588f28401102652068c4cc75e135507f4b5106 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2dbcdf33dbf61f44b29adb52338282c3d7840d0e fcd64d4d97af5d9736f31040f8ed8cd4c17e4c45 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2dbcdf33dbf61f44b29adb52338282c3d7840d0e f1516c56ac540da1769f264c3cfefe4499548a5d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2dbcdf33dbf61f44b29adb52338282c3d7840d0e 1e97c404e44991fb087c38ccd7414f2d326f9b74 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2dbcdf33dbf61f44b29adb52338282c3d7840d0e ca978f8a93d4d36841839bf2847d29b88c2591d6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.6","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 4.6 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.212 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.178 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.145 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.97 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.40 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.5 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2-rc4 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["drivers/xen/xen-scsiback.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"9c0f6894982b1f13bda220707497b25ac9c95bdb","status":"affected","version":"2dbcdf33dbf61f44b29adb52338282c3d7840d0e","versionType":"git"},{"lessThan":"a13b789497a7fdd27d4d63f5c69d23db706ef0fe","status":"affected","version":"2dbcdf33dbf61f44b29adb52338282c3d7840d0e","versionType":"git"},{"lessThan":"fa588f28401102652068c4cc75e135507f4b5106","status":"affected","version":"2dbcdf33dbf61f44b29adb52338282c3d7840d0e","versionType":"git"},{"lessThan":"fcd64d4d97af5d9736f31040f8ed8cd4c17e4c45","status":"affected","version":"2dbcdf33dbf61f44b29adb52338282c3d7840d0e","versionType":"git"},{"lessThan":"f1516c56ac540da1769f264c3cfefe4499548a5d","status":"affected","version":"2dbcdf33dbf61f44b29adb52338282c3d7840d0e","versionType":"git"},{"lessThan":"1e97c404e44991fb087c38ccd7414f2d326f9b74","status":"affected","version":"2dbcdf33dbf61f44b29adb52338282c3d7840d0e","versionType":"git"},{"lessThan":"ca978f8a93d4d36841839bf2847d29b88c2591d6","status":"affected","version":"2dbcdf33dbf61f44b29adb52338282c3d7840d0e","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["drivers/xen/xen-scsiback.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"4.6"},{"lessThan":"4.6","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.212","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.178","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.145","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.97","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.40","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.5","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2-rc4","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.212","versionStartIncluding":"4.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.178","versionStartIncluding":"4.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.145","versionStartIncluding":"4.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.97","versionStartIncluding":"4.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.40","versionStartIncluding":"4.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.5","versionStartIncluding":"4.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2-rc4","versionStartIncluding":"4.6","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"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."}],"providerMetadata":{"dateUpdated":"2026-08-15T05:52:33.521Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/9c0f6894982b1f13bda220707497b25ac9c95bdb"},{"url":"https://git.kernel.org/stable/c/a13b789497a7fdd27d4d63f5c69d23db706ef0fe"},{"url":"https://git.kernel.org/stable/c/fa588f28401102652068c4cc75e135507f4b5106"},{"url":"https://git.kernel.org/stable/c/fcd64d4d97af5d9736f31040f8ed8cd4c17e4c45"},{"url":"https://git.kernel.org/stable/c/f1516c56ac540da1769f264c3cfefe4499548a5d"},{"url":"https://git.kernel.org/stable/c/1e97c404e44991fb087c38ccd7414f2d326f9b74"},{"url":"https://git.kernel.org/stable/c/ca978f8a93d4d36841839bf2847d29b88c2591d6"}],"title":"scsi: xen: scsiback: Free unsubmitted command instead of double-putting it","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-72085","datePublished":"2026-08-15T05:52:33.521Z","dateReserved":"2026-08-09T03:40:39.904Z","dateUpdated":"2026-08-15T05:52:33.521Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-15 06:21:22","lastModifiedDate":"2026-08-15 06:21:22","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"72085","Ordinal":"1","Title":"scsi: xen: scsiback: Free unsubmitted command instead of double-","CVE":"CVE-2026-72085","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"72085","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"scsi: xen: scsiback: Free unsubmitted command instead of double-"}]}}}