Vulnerability in Linux

[ Description ]Official 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.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ Advisories ]Government CERT advisories

• CERT-FR9 Oct 2026CERTFR-2026-AVI-1289

  Multiple vulnerabilities in the Debian LTS Linux kernel Translated from French

  Multiple vulnerabilities have been discovered in the Debian LTS Linux kernel. Some of them allow an attacker to cause privilege escalation, a breach of data confidentiality and denial of service.

  CVE-2025-38237CVE-2025-39833CVE-2025-39925+1311 more CVEs
• CERT-FR2 Oct 2026CERTFR-2026-AVI-1253

  Multiple vulnerabilities in the Debian Linux kernel Translated from French

  Multiple vulnerabilities have been discovered in the Debian Linux kernel. Some of them allow an attacker to cause privilege escalation, a breach of data confidentiality and denial of service.

  CVE-2025-38237CVE-2025-39833CVE-2025-39925+1310 more CVEs
• BSI CERT-Bund24 Sep 2026WID-SEC-2026-3579

  Linux Kernel: Multiple vulnerabilities Translated from German

  CVE-2026-97615CVE-2026-97978CVE-2026-98127+590 more CVEs

[ References ]References

• git.kernel.org/stable/c/261c80a6b23e34ba98bcf3f75317e35ecf0a08f0
• git.kernel.org/stable/c/3bc7af4cefac1c583f0607f6183a67012436aad9
• git.kernel.org/stable/c/6b450c277c106c4e31411067f025d1aaa27c2a02
• git.kernel.org/stable/c/732cb6bb37fd26863d5786522fb1997e7f5865b4
• git.kernel.org/stable/c/dc9e1b6b9080dd6374cc9a38e4b53abca63c3b1b