CVE-2025-38209
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-07-04

Last updated on: 2025-11-18

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: nvme-tcp: remove tag set when second admin queue config fails Commit 104d0e2f6222 ("nvme-fabrics: reset admin connection for secure concatenation") modified nvme_tcp_setup_ctrl() to call nvme_tcp_configure_admin_queue() twice. The first call prepares for DH-CHAP negotitation, and the second call is required for secure concatenation. However, this change triggered BUG KASAN slab-use-after- free in blk_mq_queue_tag_busy_iter(). This BUG can be recreated by repeating the blktests test case nvme/063 a few times [1]. When the BUG happens, nvme_tcp_create_ctrl() fails in the call chain below: nvme_tcp_create_ctrl() nvme_tcp_alloc_ctrl() new=true ... Alloc nvme_tcp_ctrl and admin_tag_set nvme_tcp_setup_ctrl() new=true nvme_tcp_configure_admin_queue() new=true ... Succeed nvme_alloc_admin_tag_set() ... Alloc the tag set for admin_tag_set nvme_stop_keep_alive() nvme_tcp_teardown_admin_queue() remove=false nvme_tcp_configure_admin_queue() new=false nvme_tcp_alloc_admin_queue() ... Fail, but do not call nvme_remove_admin_tag_set() nvme_uninit_ctrl() nvme_put_ctrl() ... Free up the nvme_tcp_ctrl and admin_tag_set The first call of nvme_tcp_configure_admin_queue() succeeds with new=true argument. The second call fails with new=false argument. This second call does not call nvme_remove_admin_tag_set() on failure, due to the new=false argument. Then the admin tag set is not removed. However, nvme_tcp_create_ctrl() assumes that nvme_tcp_setup_ctrl() would call nvme_remove_admin_tag_set(). Then it frees up struct nvme_tcp_ctrl which has admin_tag_set field. Later on, the timeout handler accesses the admin_tag_set field and causes the BUG KASAN slab-use-after-free. To not leave the admin tag set, call nvme_remove_admin_tag_set() when the second nvme_tcp_configure_admin_queue() call fails. Do not return from nvme_tcp_setup_ctrl() on failure. Instead, jump to "destroy_admin" go-to label to call nvme_tcp_teardown_admin_queue() which calls nvme_remove_admin_tag_set().
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Meta Information
Published
2025-07-04
Last Modified
2025-11-18
Generated
2026-05-07
AI Q&A
2025-07-04
EPSS Evaluated
2026-05-05
NVD
CVE-2025-38209
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-416 The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability is a use-after-free bug in the Linux kernel's nvme-tcp driver. It occurs when the second call to configure the admin queue fails but does not properly remove the admin tag set, leading to the admin tag set being freed later while still being accessed by a timeout handler. This causes a BUG KASAN slab-use-after-free error, which can be triggered by repeating a specific test case multiple times.


How can this vulnerability impact me? :

The vulnerability can cause a kernel BUG due to use-after-free, potentially leading to system instability or crashes when the nvme-tcp driver is used. This could affect system reliability and availability.


How can this vulnerability be detected on my network or system? Can you suggest some commands?

This vulnerability can be detected by reproducing the BUG KASAN slab-use-after-free in blk_mq_queue_tag_busy_iter() using the blktests test case nvme/063 repeatedly. Running the blktests suite, specifically the nvme/063 test case multiple times, can help identify the issue.


What immediate steps should I take to mitigate this vulnerability?

To mitigate this vulnerability, ensure that the Linux kernel version you are using includes the fix where nvme_remove_admin_tag_set() is called when the second nvme_tcp_configure_admin_queue() call fails. This prevents the admin tag set from being left dangling and avoids the use-after-free bug. If possible, update to a kernel version that contains the commit 104d0e2f6222 or later that addresses this issue.


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