CVE-2026-93781— scsi: core: Do not block on tag allocation in scsi_eh_lock_door()
Quick assessment
Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
在 Linux 内核中，已修复以下漏洞： scsi: core: 在 scsi_eh_lock_door() 中避免在标签分配时阻塞 在 中被调用，此时主机仍处于 （恢复）状态，即尚未切换回 （运行）状态，且 尚未重启队列。该函数通过 分配一个请求，且未传递任何标志，因此当所有标签均已被占用时， 可能会阻塞等待可用的调度标签（sched tag）。 这些标签可能被由 在错误处理期间重新入队的命令持有。此类命令必须等到主机退出 状态并调用 后才能被分发——而这一操作仅在 返回之后才会发生。 这就形成了一个循环依赖：
Possible ATT&CK Techniques 1 AI
T1499 · Endpoint Denial of ServiceAffected Version Matrix 12
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Linux | Linux | 6e68af666f5336254b5715dca591026b7324499a< 3bc7af4cefac1c583f0607f6183a67012436aad9 |
affected |
6e68af666f5336254b5715dca591026b7324499a< 6b450c277c106c4e31411067f025d1aaa27c2a02 |
affected | ||
6e68af666f5336254b5715dca591026b7324499a< 261c80a6b23e34ba98bcf3f75317e35ecf0a08f0 |
affected | ||
6e68af666f5336254b5715dca591026b7324499a< dc9e1b6b9080dd6374cc9a38e4b53abca63c3b1b |
affected | ||
6e68af666f5336254b5715dca591026b7324499a< 732cb6bb37fd26863d5786522fb1997e7f5865b4 |
affected | ||
2.6.16 |
affected | ||
< 2.6.16 |
unaffected | ||
6.1.189≤ 6.1.* |
unaffected | ||
| … +4 more rows | |||
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I. Basic Information for CVE-2026-93781
Vulnerability Information
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Vulnerability Title
scsi: core: Do not block on tag allocation in scsi_eh_lock_door()
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
scsi: core: Do not block on tag allocation in scsi_eh_lock_door()
scsi_eh_lock_door() is called from scsi_restart_operations() while the
host is still in the SHOST_RECOVERY state, i.e. before the host is
switched back to SHOST_RUNNING and scsi_run_host_queues() restarts the
queues. It allocates a request via scsi_alloc_request() with no flags,
so blk_mq_get_tag() may block waiting for a free sched tag when all tags
are already in use.
Those tags can be held by commands that were just requeued by
scsi_eh_flush_done_q() during error handling. Such commands cannot be
dispatched until the host leaves SHOST_RECOVERY and
scsi_run_host_queues() is called - which only happens *after*
scsi_eh_lock_door() returns.
This forms a circular dependency:
- scsi_eh_lock_door(), running in the SCSI error handler thread, waits
for a sched tag held by a requeued command;
- the requeued command cannot complete and release its sched tag until
the error handler thread leaves scsi_restart_operations() and restart
the queues.
For devices with a single driver tag (e.g. USB storage) it is a
guaranteed deadlock and I/O that can never be submitted. This problem
has also been reproduced in our environment.
Locking the door is a best-effort operation, and scsi_eh_lock_door()
already returns silently when the request allocation fails. Pass
BLK_MQ_REQ_NOWAIT to scsi_alloc_request() so the allocation fails
instead of blocking when no tag is available. This breaks the circular
dependency and allows the error handler to finish restarting the queues,
after which the pending commands are dispatched normally.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Affected Products
II. Public POCs for CVE-2026-93781
| # | POC Description | Source Link | Shenlong Link |
|---|
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Patches & Fixes for CVE-2026-93781 (5)
Same Patch Batch · Linux · 2026-09-24 · 234 CVEs total
| CVE-2026-93207 | 9.8 CRITICAL | SUNRPC: Zero rpc_gss_wire_cred at svcauth_gss_decode_credbody() entry |
| CVE-2026-97413 | 9.8 CRITICAL | RDMA/rtrs-srv: Fix integer underflow in process_read and process_write |
| CVE-2026-93228 | 9.1 CRITICAL | svcrdma: Reject Write/Reply chunks with segcount 0 |
| CVE-2026-93793 | 8.8 HIGH | wifi: iwlwifi: mvm: validate TX_CMD response layout |
| CVE-2026-93799 | 8.8 HIGH | wifi: iwlwifi: mvm: validate sta_id in BA window status notif |
| CVE-2026-93790 | 8.8 HIGH | wifi: iwlwifi: mvm: fix out-of-bounds tid_data access in BA notif |
| CVE-2026-93806 | 8.8 HIGH | wifi: cfg80211: validate assoc response length before status and IE access |
| CVE-2026-97442 | 8.8 HIGH | wifi: ath11k: fix invalid data access in ath11k_dp_rx_h_undecap_nwifi |
| CVE-2026-97509 | 8.8 HIGH | thunderbolt: Keep XDomain reference during the lifetime of a service |
| CVE-2026-97409 | 8.8 HIGH | nvme-fc: Do not cancel requests in io target before it is initialized |
| CVE-2026-93280 | 8.8 HIGH | greybus: audio: bound the topology section sizes against the fetched size |
| CVE-2026-93284 | 8.8 HIGH | drm/pagemap: dma-unmap pages before handling migration errors |
| CVE-2026-97451 | 8.4 HIGH | ACPICA: Fix integer overflow in acpi_ex_opcode_3A_1T_1R() (mid_op) |
| CVE-2026-97452 | 8.4 HIGH | ACPICA: Prevent adding invalid references |
| CVE-2026-97455 | 8.4 HIGH | ACPICA: Fix use-after-free in acpi_ds_terminate_control_method() |
| CVE-2026-97450 | 8.4 HIGH | ACPICA: validate handler object type in two places |
| CVE-2026-93827 | 8.4 HIGH | virtio-fs: avoid double-free on failed queue setup |
| CVE-2026-97433 | 8.2 HIGH | nvme: validate FDP configuration descriptor sizes |
| CVE-2026-93786 | 8.1 HIGH | ksmbd: preserve VFS inherited POSIX ACL mask |
| CVE-2026-93787 | 8.1 HIGH | smb: client: bound dirent name against end of SMB response in cifs_filldir |
Showing top 20 of 234 CVEs. View all on vendor page → →
IV. Related Vulnerabilities
Same product: Linux
-
CVE-2026-98384
bpf: Fix out-of-bounds read of sk_protocol in bpf_sock_destr -
CVE-2026-98383
bpf: Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL -
CVE-2026-98382
bpf: Reject dev-bound-only programs on other devices -
CVE-2026-98381
veth: manage XDP program pointers during channel resize -
CVE-2026-98380
net/sched: reject IDR error pointers when deleting actions
Same vendor: Linux
-
CVE-2026-98384
bpf: Fix out-of-bounds read of sk_protocol in bpf_sock_destr -
CVE-2026-98383
bpf: Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL -
CVE-2026-98382
bpf: Reject dev-bound-only programs on other devices -
CVE-2026-98381
veth: manage XDP program pointers during channel resize -
CVE-2026-98380
net/sched: reject IDR error pointers when deleting actions
V. Comments for CVE-2026-93781
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