{"id":"CVE-2026-43054","title":"scsi: target: tcm_loop: Drain commands in target_reset handler","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nscsi: target: tcm_loop: Drain commands in target_reset handler\n\ntcm_loop_target_reset() violates the SCSI EH contract: it returns SUCCESS\nwithout draining any in-flight…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= e0eb5d38b732b011cd9ed5b1bf9f59b83c2500d3 < 757c43c692294cdfad31390accc0e90429b2ef8a","Linux >= e0eb5d38b732b011cd9ed5b1bf9f59b83c2500d3 < 103f79e4949513247d763c6e7f3cbbf62017afdf","Linux >= e0eb5d38b732b011cd9ed5b1bf9f59b83c2500d3 < 15f5241d5a52364a7e7867b49128b0442dbcad9d","Linux >= e0eb5d38b732b011cd9ed5b1bf9f59b83c2500d3 < 7cbd69aaa507b1245240a28022bf5da0f07c68d9","Linux >= e0eb5d38b732b011cd9ed5b1bf9f59b83c2500d3 < a836054ea81014117ec6b73529a21626a9e1f829","Linux >= e0eb5d38b732b011cd9ed5b1bf9f59b83c2500d3 < 05ac3754467363558a0a54ae4bb7c89b2c9574cf","Linux >= e0eb5d38b732b011cd9ed5b1bf9f59b83c2500d3 < 1333eee56cdf3f0cf67c6ab4114c2c9e0a952026","Linux 5.13"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-11-06T15:27:27.923024Z"},"published":"2026-05-01","updated":"2026-11-06","sourceUpdated":"2026-11-06T15:32:28.903Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-43054","references":[{"url":"https://git.kernel.org/stable/c/757c43c692294cdfad31390accc0e90429b2ef8a"},{"url":"https://git.kernel.org/stable/c/103f79e4949513247d763c6e7f3cbbf62017afdf"},{"url":"https://git.kernel.org/stable/c/15f5241d5a52364a7e7867b49128b0442dbcad9d"},{"url":"https://git.kernel.org/stable/c/7cbd69aaa507b1245240a28022bf5da0f07c68d9"},{"url":"https://git.kernel.org/stable/c/a836054ea81014117ec6b73529a21626a9e1f829"},{"url":"https://git.kernel.org/stable/c/05ac3754467363558a0a54ae4bb7c89b2c9574cf"},{"url":"https://git.kernel.org/stable/c/1333eee56cdf3f0cf67c6ab4114c2c9e0a952026"}],"tags":["cve.org"],"epss":0.00114,"epssPercentile":0.01492,"ingestedAt":"2026-11-06T15:54:04.030Z","slug":"CVE-2026-43054","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nscsi: target: tcm_loop: Drain commands in target_reset handler\n\ntcm_loop_target_reset() violates the SCSI EH contract: it returns SUCCESS\nwithout draining any in-flight commands.  The SCSI EH documentation\n(scsi_eh.rst) requires that when a reset handler returns SUCCESS the driver\nhas made lower layers \"forget about timed out scmds\" and is ready for new\ncommands.  Every other SCSI LLD (virtio_scsi, mpt3sas, ipr, scsi_debug,\nmpi3mr) enforces this by draining or completing outstanding commands before\nreturning SUCCESS.\n\nBecause tcm_loop_target_reset() doesn't drain, the SCSI EH reuses in-flight\nscsi_cmnd structures for recovery commands (e.g. TUR) while the target core\nstill has async completion work queued for the old se_cmd.  The memset in\nqueuecommand zeroes se_lun and lun_ref_active, causing\ntransport_lun_remove_cmd() to skip its percpu_ref_put().  The leaked LUN\nreference prevents transport_clear_lun_ref() from completing, hanging\nconfigfs LUN unlink forever in D-state:\n\n  INFO: task rm:264 blocked for more than 122 seconds.\n  rm              D    0   264    258 0x00004000\n  Call Trace:\n   __schedule+0x3d0/0x8e0\n   schedule+0x36/0xf0\n   transport_clear_lun_ref+0x78/0x90 [target_core_mod]\n   core_tpg_remove_lun+0x28/0xb0 [target_core_mod]\n   target_fabric_port_unlink+0x50/0x60 [target_core_mod]\n   configfs_unlink+0x156/0x1f0 [configfs]\n   vfs_unlink+0x109/0x290\n   do_unlinkat+0x1d5/0x2d0\n\nFix this by making tcm_loop_target_reset() actually drain commands:\n\n 1. Issue TMR_LUN_RESET via tcm_loop_issue_tmr() to drain all commands that\n    the target core knows about (those not yet CMD_T_COMPLETE).\n\n 2. Use blk_mq_tagset_busy_iter() to iterate all started requests and\n    flush_work() on each se_cmd — this drains any deferred completion work\n    for commands that already had CMD_T_COMPLETE set before the TMR (which\n    the TMR skips via __target_check_io_state()).  This is the same pattern\n    used by mpi3mr, scsi_debug, and libsas to drain outstanding commands\n    during reset.\n\n## Affected\n\n- `Linux >= e0eb5d38b732b011cd9ed5b1bf9f59b83c2500d3 < 757c43c692294cdfad31390accc0e90429b2ef8a`\n- `Linux >= e0eb5d38b732b011cd9ed5b1bf9f59b83c2500d3 < 103f79e4949513247d763c6e7f3cbbf62017afdf`\n- `Linux >= e0eb5d38b732b011cd9ed5b1bf9f59b83c2500d3 < 15f5241d5a52364a7e7867b49128b0442dbcad9d`\n- `Linux >= e0eb5d38b732b011cd9ed5b1bf9f59b83c2500d3 < 7cbd69aaa507b1245240a28022bf5da0f07c68d9`\n- `Linux >= e0eb5d38b732b011cd9ed5b1bf9f59b83c2500d3 < a836054ea81014117ec6b73529a21626a9e1f829`\n- `Linux >= e0eb5d38b732b011cd9ed5b1bf9f59b83c2500d3 < 05ac3754467363558a0a54ae4bb7c89b2c9574cf`\n- `Linux >= e0eb5d38b732b011cd9ed5b1bf9f59b83c2500d3 < 1333eee56cdf3f0cf67c6ab4114c2c9e0a952026`\n- `Linux 5.13`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}