RDMA/rxe: Fix race condition in QP timer handlers
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: RDMA/rxe: Fix race condition in QP timer handlers I encontered the following warning: WARNING: drivers/infiniband/sw/rxe/rxe_task.c:249 at rxe_sched_task+0x1c8/0x238 [rdma_rxe], CPU#0: swapper/0/0 ... libsha1 [last unloaded: ip6_udp_tunnel] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G C 6.19.0-rc5-64k-v8+ #37 PREEMPT Tainted: [C]=CRAP Hardware name: Raspberry Pi 4 Model B Rev 1.2 Call trace: rxe_sched_task+0x1c8/0x238 [rdma_rxe] (P) retransmit_timer+0x130/0x188 [rdma_rxe] call_timer_fn+0x68/0x4d0 __run_timers+0x630/0x888 ... WARNING: drivers/infiniband/sw/rxe/rxe_task.c:38 at rxe_sched_task+0x1c0/0x238 [rdma_rxe], CPU#0: swapper/0/0 ... WARNING: drivers/infiniband/sw/rxe/rxe_task.c:111 at do_work+0x488/0x5c8 [rdma_rxe], CPU#3: kworker/u17:4/93400 ... refcount_t: underflow; use-after-free. WARNING: lib/refcount.c:28 at refcount_warn_saturate+0x138/0x1a0, CPU#3: kworker/u17:4/93400 The issue is caused by a race condition between retransmit_timer() and rxe_destroy_qp, leading to the Queue Pair's (QP) reference count dropping to zero during timer handler execution. It seems this warning is harmless because rxe_qp_do_cleanup() will flush all pending timers and requests. Example of flow causing the issue: CPU0 CPU1 retransmit_timer() { spin_lock_irqsave rxe_destroy_qp() __rxe_cleanup() __rxe_put() // qp->ref_count decrease to 0 rxe_qp_do_cleanup() { if (qp->valid) { rxe_sched_task() { WARN_ON(rxe_read(task->qp) <= 0); } } spin_unlock_irqrestore } spin_lock_irqsave qp->valid = 0 spin_unlock_irqrestore } Ensure the QP's reference count is maintained and its validity is checked within the timer callbacks by adding calls to rxe_get(qp) and corresponding rxe_put(qp) after use.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 6.4 and later | 6.6.128, 6.12.75, 6.18.14, 6.19.4, 7.0 | Patch available | CNA |
- Linux VendorLinux Affected 6.4 and later Fixed in 6.6.128, 6.12.75, 6.18.14, 6.19.4, 7.0 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 6.4 to before 6.6.128; 6.7 to before 6.12.75; 6.13 to before 6.18.14; 6.19 to before 6.19.4 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 6.4 to before 6.6.128; 6.7 to before 6.12.75; 6.13 to before 6.18.14; 6.19 to before 6.19.4 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.6.128, 6.12.75, 6.18.14, 6.19.4, 7.0
Red Hat 3 advisories
- RHSA-2026:77219 Released 2026-10-08 · Red Hat rating Importantkernel security, bug fix, and enhancement update
- Red Hat CodeReady Linux Builder EUS (v.9.6) kernel-tools-libs-devel-5.14.0-570.147.1.el9_6, libperf-5.14.0-570.147.1.el9_6
- Red Hat Enterprise Linux AppStream EUS (v.9.6) kernel-64k-debug-devel-5.14.0-570.147.1.el9_6, kernel-64k-debug-devel-matched-5.14.0-570.147.1.el9_6, kernel-64k-devel-5.14.0-570.147.1.el9_6 +12
- Red Hat Enterprise Linux BaseOS EUS (v.9.6) kernel-5.14.0-570.147.1.el9_6, kernel-64k-5.14.0-570.147.1.el9_6, kernel-64k-core-5.14.0-570.147.1.el9_6 +28
- Red Hat Enterprise Linux Real Time EUS (v.9.6) kernel-rt-5.14.0-570.147.1.el9_6, kernel-rt-64k-5.14.0-570.147.1.el9_6, kernel-rt-64k-core-5.14.0-570.147.1.el9_6 +21
- Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) kernel-rt-5.14.0-570.147.1.el9_6, kernel-rt-core-5.14.0-570.147.1.el9_6, kernel-rt-debug-5.14.0-570.147.1.el9_6 +11
- RHSA-2026:77218 Released 2026-10-07 · Red Hat rating Importantkernel security update
- Red Hat Enterprise Linux AppStream E4S (v.9.4) kernel-64k-debug-devel-5.14.0-427.154.1.el9_4, kernel-64k-debug-devel-matched-5.14.0-427.154.1.el9_4, kernel-64k-devel-5.14.0-427.154.1.el9_4 +11
- Red Hat Enterprise Linux BaseOS E4S (v.9.4) bpftool-7.3.0-427.154.1.el9_4, kernel-5.14.0-427.154.1.el9_4, kernel-64k-5.14.0-427.154.1.el9_4 +29
- Red Hat Enterprise Linux Real Time E4S (v.9.4) kernel-rt-5.14.0-427.154.1.el9_4, kernel-rt-core-5.14.0-427.154.1.el9_4, kernel-rt-debug-5.14.0-427.154.1.el9_4 +9
- Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4) kernel-rt-5.14.0-427.154.1.el9_4, kernel-rt-core-5.14.0-427.154.1.el9_4, kernel-rt-debug-5.14.0-427.154.1.el9_4 +11
- RHSA-2026:68570 Released 2026-09-17 · Red Hat rating Importantkernel security, bug fix, and enhancement update
- Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.49.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.49.1.el9_8, kernel-64k-devel-5.14.0-687.49.1.el9_8 +12
- Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.49.1.el9_8, kernel-64k-5.14.0-687.49.1.el9_8, kernel-64k-core-5.14.0-687.49.1.el9_8 +28
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.49.1.el9_8, libperf-5.14.0-687.49.1.el9_8
- Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.49.1.el9_8, kernel-rt-64k-5.14.0-687.49.1.el9_8, kernel-rt-64k-core-5.14.0-687.49.1.el9_8 +21
- Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.49.1.el9_8, kernel-rt-core-5.14.0-687.49.1.el9_8, kernel-rt-debug-5.14.0-687.49.1.el9_8 +9
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat CodeReady Linux Builder EUS (v.9.6) | Fixed | RHSA-2026:77219 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2026:68570 |
| Red Hat Enterprise Linux AppStream E4S (v.9.4) | Fixed | RHSA-2026:77218 |
| Red Hat Enterprise Linux AppStream EUS (v.9.6) | Fixed | RHSA-2026:77219 |
| Red Hat Enterprise Linux BaseOS (v. 9) | Fixed | RHSA-2026:68570 |
| Red Hat Enterprise Linux BaseOS E4S (v.9.4) | Fixed | RHSA-2026:77218 |
| Red Hat Enterprise Linux BaseOS EUS (v.9.6) | Fixed | RHSA-2026:77219 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) | Fixed | RHSA-2026:68570 |
| Red Hat Enterprise Linux Real Time (v. 9) | Fixed | RHSA-2026:68570 |
| Red Hat Enterprise Linux Real Time E4S (v.9.4) | Fixed | RHSA-2026:77218 |
| Red Hat Enterprise Linux Real Time EUS (v.9.6) | Fixed | RHSA-2026:77219 |
| Red Hat Enterprise Linux Real Time for NFV (v. 9) | Fixed | RHSA-2026:68570 |
| Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4) | Fixed | RHSA-2026:77218 |
| Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) | Fixed | RHSA-2026:77219 |
Not affected: 5 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2026-45910
- 2026-10-03 Alias added: GHSA-ghcq-8j2m-vfjm
- 2026-10-07 Fix available: RHSA-2026:77218 · Red Hat
- 2026-10-07 Fix available: Red Hat Enterprise Linux AppStream E4S (v.9.4), Red Hat Enterprise Linux BaseOS E4S (v.9.4), Red Hat Enterprise Linux Real Time E4S (v.9.4) +1 · Red Hat
- 2026-10-09 Fix available: RHSA-2026:77219 · Red Hat
- 2026-10-09 Fix available: Red Hat CodeReady Linux Builder EUS (v.9.6), Red Hat Enterprise Linux AppStream EUS (v.9.6), Red Hat Enterprise Linux BaseOS EUS (v.9.6) +2 · Red Hat
- 2026-10-16 CISA SSVC decision points changed
- 2026-10-19 Weakness changed · CISA ADP
- 2026-10-29 Affected versions changed · Red Hat
References
Patch 5
- https://git.kernel.org/stable/c/756c93d6df7c3bc599f6590b8e5afead6a41de1c
- https://git.kernel.org/stable/c/3c2ae79fb19dfd67341c14f1e78a5f1744eacfe2
- https://git.kernel.org/stable/c/5ae9da022ee3c97e6469eabcddce9271501ddbad
- https://git.kernel.org/stable/c/da379ca16af3722f159860d91a99cb6976a7500f
- https://git.kernel.org/stable/c/87bf646921430e303176edc4eb07c30160361b73
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Sources
- CVE-2026-45910 · CVE Program
- CVE-2026-45910 · NVD
- FIRST EPSS
- GHSA-ghcq-8j2m-vfjm · GitHub Advisory Database · CC BY 4.0
- CVE-2026-45910 · Red Hat security data · CC BY 4.0
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