# CVE-2024-47696: RDMA/iwcm: Fix WARNING:at_kernel/workqueue.c:#check_flush_dependency > A use-after-free vulnerability in the Linux kernel RDMA/iwcm module can cause a deadlock and system crash during CM ID destruction. - **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 21 Oct 2024 - **Updated:** 15 Oct 2026 - **Also known as:** AZL-50818, AZL-50949, BELL-CVE-2024-47696, DEBIAN-CVE-2024-47696, GHSA-36v8-3fmp-p728, UBUNTU-CVE-2024-47696 ## What is CVE-2024-47696? CVE-2024-47696 is a high-severity use after free vulnerability in Linux kernel, published on 21 Oct 2024. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description In the Linux kernel, the following vulnerability has been resolved: RDMA/iwcm: Fix WARNING:at_kernel/workqueue.c:#check_flush_dependency In the commit aee2424246f9 ("RDMA/iwcm: Fix a use-after-free related to destroying CM IDs"), the function flush_workqueue is invoked to flush the work queue iwcm_wq. But at that time, the work queue iwcm_wq was created via the function alloc_ordered_workqueue without the flag WQ_MEM_RECLAIM. Because the current process is trying to flush the whole iwcm_wq, if iwcm_wq doesn't have the flag WQ_MEM_RECLAIM, verify that the current process is not reclaiming memory or running on a workqueue which doesn't have the flag WQ_MEM_RECLAIM as that can break forward-progress guarantee leading to a deadlock. The call trace is as below: [ 125.350876][ T1430] Call Trace: [ 125.356281][ T1430] [ 125.361285][ T1430] ? __warn (kernel/panic.c:693) [ 125.367640][ T1430] ? check_flush_dependency (kernel/workqueue.c:3706 (discriminator 9)) [ 125.375689][ T1430] ? report_bug (lib/bug.c:180 lib/bug.c:219) [ 125.382505][ T1430] ? handle_bug (arch/x86/kernel/traps.c:239) [ 125.388987][ T1430] ? exc_invalid_op (arch/x86/kernel/traps.c:260 (discriminator 1)) [ 125.395831][ T1430] ? asm_exc_invalid_op (arch/x86/include/asm/idtentry.h:621) [ 125.403125][ T1430] ? check_flush_dependency (kernel/workqueue.c:3706 (discriminator 9)) [ 125.410984][ T1430] ? check_flush_dependency (kernel/workqueue.c:3706 (discriminator 9)) [ 125.418764][ T1430] __flush_workqueue (kernel/workqueue.c:3970) [ 125.426021][ T1430] ? __pfx___might_resched (kernel/sched/core.c:10151) [ 125.433431][ T1430] ? destroy_cm_id (drivers/infiniband/core/iwcm.c:375) iw_cm [ 125.441209][ T1430] ? __pfx___flush_workqueue (kernel/workqueue.c:3910) [ 125.473900][ T1430] ? _raw_spin_lock_irqsave (arch/x86/include/asm/atomic.h:107 include/linux/atomic/atomic-arch-fallback.h:2170 include/linux/atomic/atomic-instrumented.h:1302 include/asm-generic/qspinlock.h:111 include/linux/spinlock.h:187 include/linux/spinlock_api_smp.h:111 kernel/locking/spinlock.c:162) [ 125.473909][ T1430] ? __pfx__raw_spin_lock_irqsave (kernel/locking/spinlock.c:161) [ 125.482537][ T1430] _destroy_id (drivers/infiniband/core/cma.c:2044) rdma_cm [ 125.495072][ T1430] nvme_rdma_free_queue (drivers/nvme/host/rdma.c:656 drivers/nvme/host/rdma.c:650) nvme_rdma [ 125.505827][ T1430] nvme_rdma_reset_ctrl_work (drivers/nvme/host/rdma.c:2180) nvme_rdma [ 125.505831][ T1430] process_one_work (kernel/workqueue.c:3231) [ 125.515122][ T1430] worker_thread (kernel/workqueue.c:3306 kernel/workqueue.c:3393) [ 125.515127][ T1430] ? __pfx_worker_thread (kernel/workqueue.c:3339) [ 125.531837][ T1430] kthread (kernel/kthread.c:389) [ 125.539864][ T1430] ? __pfx_kthread (kernel/kthread.c:342) [ 125.550628][ T1430] ret_from_fork (arch/x86/kernel/process.c:147) [ 125.558840][ T1430] ? __pfx_kthread (kernel/kthread.c:342) [ 125.558844][ T1430] ret_from_fork_asm (arch/x86/entry/entry_64.S:257) [ 125.566487][ T1430] [ 125.566488][ T1430] ---[ end trace 0000000000000000 ]--- Weakness: CWE-416 (Use After Free) ## Which versions are affected by CVE-2024-47696? It affects 1 product. Products: Linux kernel. ## How do I fix CVE-2024-47696? Apply the vendor's patch. ## Is CVE-2024-47696 being exploited? There is no known exploitation of CVE-2024-47696 in the wild and no public exploit code. ## Other vulnerabilities in Linux kernel - [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild) - [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild) - [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild) - [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild) - [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2024-47696 and fix it if it is affected. What it is: CVE-2024-47696 is a high-severity use after free vulnerability in Linux kernel, published on 21 Oct 2024. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2024-47696 in the wild and no public exploit code. Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2024-47696/ (Markdown: https://insights.sbomify.com/CVE-2024-47696/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2024-47696 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-47696 - OSV: https://osv.dev/vulnerability/CVE-2024-47696 --- From sbomify Insights: https://insights.sbomify.com/CVE-2024-47696/ Summaries are generated and may contain mistakes; the official description above is the record.