Summary
In the Linux kernel, the following vulnerability has been resolved: RDMA/iwcm: Fix use-after...
In the Linux kernel, the following vulnerability has been resolved:
RDMA/iwcm: Fix use-after-free of work objects after cm_id destruction
The commit 59c68ac31e15 ("iw_cm: free cm_id resources on the last
deref") simplified cm_id resource management by freeing cm_id once all
references to the cm_id were removed. The references are removed either
upon completion of iw_cm event handlers or when the application destroys
the cm_id. This commit introduced the use-after-free condition where
cm_id_private object could still be in use by event handler works during
the destruction of cm_id. The commit aee2424246f9 ("RDMA/iwcm: Fix a
use-after-free related to destroying CM IDs") addressed this use-after-
free by flushing all pending works at the cm_id destruction.
However, still another use-after-free possibility remained. It happens
with the work objects allocated for each cm_id_priv within
alloc_work_entries() during cm_id creation, and subsequently freed in
dealloc_work_entries() once all references to the cm_id are removed.
If the cm_id's last reference is decremented in the event handler work,
the work object for the work itself gets removed, and causes the use-
after-free BUG below:
BUG: KASAN: slab-use-after-free in __pwq_activate_work+0x1ff/0x250
Read of size 8 at addr ffff88811f9cf800 by task kworker/u16:1/147091
CPU: 2 UID: 0 PID: 147091 Comm: kworker/u16:1 Not tainted 6.15.0-rc2+ #27 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014
Workqueue: 0x0 (iw_cm_wq)
Call Trace:
dump_stack_lvl+0x6a/0x90
print_report+0x174/0x554
? __virt_addr_valid+0x208/0x430
? __pwq_activate_work+0x1ff/0x250
kasan_report+0xae/0x170
? __pwq_activate_work+0x1ff/0x250
__pwq_activate_work+0x1ff/0x250
pwq_dec_nr_in_flight+0x8c5/0xfb0
process_one_work+0xc11/0x1460
? __pfx_process_one_work+0x10/0x10
? assign_work+0x16c/0x240
worker_thread+0x5ef/0xfd0
? __pfx_worker_thread+0x10/0x10
kthread+0x3b0/0x770
? __pfx_kthread+0x10/0x10
? rcu_is_watching+0x11/0xb0
? _raw_spin_unlock_irq+0x24/0x50
? rcu_is_watching+0x11/0xb0
? __pfx_kthread+0x10/0x10
ret_from_fork+0x30/0x70
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1a/0x30
Allocated by task 147416:
kasan_save_stack+0x2c/0x50
kasan_save_track+0x10/0x30
__kasan_kmalloc+0xa6/0xb0
alloc_work_entries+0xa9/0x260 [iw_cm]
iw_cm_connect+0x23/0x4a0 [iw_cm]
rdma_connect_locked+0xbfd/0x1920 [rdma_cm]
nvme_rdma_cm_handler+0x8e5/0x1b60 [nvme_rdma]
cma_cm_event_handler+0xae/0x320 [rdma_cm]
cma_work_handler+0x106/0x1b0 [rdma_cm]
process_one_work+0x84f/0x1460
worker_thread+0x5ef/0xfd0
kthread+0x3b0/0x770
ret_from_fork+0x30/0x70
ret_from_fork_asm+0x1a/0x30
Freed by task 147091:
kasan_save_stack+0x2c/0x50
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x4b/0x70
kfree+0x13a/0x4b0
dealloc_work_entries+0x125/0x1f0 [iw_cm]
iwcm_deref_id+0x6f/0xa0 [iw_cm]
cm_work_handler+0x136/0x1ba0 [iw_cm]
process_one_work+0x84f/0x1460
worker_thread+0x5ef/0xfd0
kthread+0x3b0/0x770
ret_from_fork+0x30/0x70
ret_from_fork_asm+0x1a/0x30
Last potentially related work creation:
kasan_save_stack+0x2c/0x50
kasan_record_aux_stack+0xa3/0xb0
__queue_work+0x2ff/0x1390
queue_work_on+0x67/0xc0
cm_event_handler+0x46a/0x820 [iw_cm]
siw_cm_upcall+0x330/0x650 [siw]
siw_cm_work_handler+0x6b9/0x2b20 [siw]
process_one_work+0x84f/0x1460
worker_thread+0x5ef/0xfd0
kthread+0x3b0/0x770
ret_from_fork+0x30/0x70
ret_from_fork_asm+0x1a/0x30
This BUG is reproducible by repeating the blktests test case nvme/061
for the rdma transport and the siw driver.
To avoid the use-after-free of cm_id_private work objects, ensure that
the last reference to the cm_id is decremented not in the event handler
works, but in the cm_id destruction context. For that purpose, mo
---truncated---
Impact
Memory is accessed after it has been freed, leading to undefined behavior in native code. Typical impact: memory corruption, crash, or potential code execution.
CVE-2025-38211 has a CVSS score of 7.8 (High). The vector is requires local access, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2025-38211? CVE-2025-38211 is a high-severity use after free vulnerability. No fixed version is listed yet. Memory is accessed after it has been freed, leading to undefined behavior in native code.
- How severe is CVE-2025-38211? CVE-2025-38211 has a CVSS score of 7.8 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Is there a fix for CVE-2025-38211? No fixed version is listed for CVE-2025-38211 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2025-38211 exploitable, and should I be worried? Whether CVE-2025-38211 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-38211 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.