Kernel crash via unlocked RDMA event queue race
Published Sep 11, 2026 · Updated Sep 11, 2026
A race condition in Linux 6.18 allows local users to crash the kernel or leave RDMA writers hung through connection-manager writes. ucma_write_cm_event() rereads ctx->file while ucma_migrate_id() can replace it, linking a uevent into one file's list while another file's mutex is held. The world-writable /dev/infiniband/rdma_cm interface makes the path reachable without privileges or RDMA hardware, and successful races corrupt the event list and can strand a mutex indefinitely.
Summary
What happened
A race condition in Linux 6.18 allows local users to crash the kernel or leave RDMA writers hung through connection-manager writes. ucma_write_cm_event() rereads ctx->file while ucma_migrate_id() can replace it, linking a uevent into one file's list while another file's mutex is held. The world-writable /dev/infiniband/rdma_cm interface makes the path reachable without privileges or RDMA hardware, and successful races corrupt the event list and can strand a mutex indefinitely.
The record
- CVE
- CVE-2026-89507
- Published
- Sep 11, 2026
- Updated
- Sep 11, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 11, 2026CVE publishedPublication date reported by the CVE source.
- Sep 11, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=6.18
- Affected versionversion=a3c9d0fcd3715541bbf97da2ddde9d032e2fe6d5 <0be1955040a2eceed0ecfc387fdc92305411d273
- Affected versionversion=a3c9d0fcd3715541bbf97da2ddde9d032e2fe6d5 <4f8bb11dd2ff365e7cff1c9964ab4607292d364e
- Affected versionversion=a3c9d0fcd3715541bbf97da2ddde9d032e2fe6d5 <f4cc21c6a8e9d392871477f9fd98d68e5ad80272
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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