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CVE-2026-72473— xprtrdma: Decouple req recycling from RPC completion

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel 5.3版本存在安全漏洞，该漏洞源于xprtrdma中rl_kref引用计数管理不当，可能导致请求在硬件仍读取发送缓冲区时被释放，造成释放后重用。

CVSS 9.8 · Critical EPSS 0.66% · P49

Possible ATT&CK Techniques 1 AI

T1135 · Network Share Discovery

Affected Version Matrix 14

VendorProduct Version RangeStatus
Linux Linux 0ab115237025f5e379620bbcd56a02697d07b002< 740975054a1970c0cf15f70ac39724a064f45847 affected
0ab115237025f5e379620bbcd56a02697d07b002< 9f3d9b68c1c6c51746e5ecdb52b2e6a2901de37e affected
0ab115237025f5e379620bbcd56a02697d07b002< e7632089523acddcdd8f090ad19e96fb3107b04d affected
0ab115237025f5e379620bbcd56a02697d07b002< 53442c7d0c888e51b8bc3da196970a669cc6b294 affected
0ab115237025f5e379620bbcd56a02697d07b002< 8203f760a72bd39a3b66bc4eff0aa272a99fe22b affected
0ab115237025f5e379620bbcd56a02697d07b002< e786233d2e0bbff9a82e43f02ae3a46ab4b08ec3 affected
5.3 affected
< 5.3 unaffected
… +6 more rows
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I. Basic Information for CVE-2026-72473

Vulnerability Information
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Vulnerability Title
xprtrdma: Decouple req recycling from RPC completion
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: xprtrdma: Decouple req recycling from RPC completion rl_kref formerly served two distinct lifetimes through a single refcount: it gated when a Reply could wake its RPC task, and it gated when an rpcrdma_req could return to its free pool. The marshal path took the Send-side reference only when SGEs needed DMA-unmap (sc_unmap_count > 0), which made a Send carrying only pre-registered buffers an exception: the Reply handler dropped rl_kref from 1 to 0 and freed the req while the HCA might still be DMA-reading from its send buffer. Give rl_kref a narrower job. The RPC layer takes one reference when slot allocation hands a req out. rpcrdma_prepare_send_sges() takes a Send-side reference unconditionally after WR preparation succeeds. xprt_rdma_free_slot() and xprt_rdma_bc_free_rqst() drop the RPC-layer reference; rpcrdma_sendctx_unmap() drops the Send-side reference. The req returns to its free pool only after both owners have signed off. The existing kref_init(&req->rl_kref) call in rpcrdma_prepare_send_sges() is removed. Initialization moves to the slot-allocation paths (xprt_rdma_alloc_slot and rpcrdma_bc_rqst_get), and the release callback re-arms rl_kref before the req returns to a free pool. A re-init in the marshal path would discard the RPC-layer reference that already exists on entry. Three invariants follow: - Any rpcrdma_req held by an rpc_rqst has rl_kref >= 1. xprt_rdma_alloc_slot(), rpcrdma_bc_rqst_get(), and the backlog-wake branch in xprt_rdma_alloc_slot() each kref_init rl_kref before publishing the req. Without this invariant, an RPC task that aborts between slot allocation and marshal (gss_refresh failure or signal during call_connect, for example) would drive xprt_release() -> xprt_rdma_free_slot() -> kref_put against a refcount of zero, saturating refcount_t and stranding the slot. - The Send-side reference is taken only after WR prep succeeds. A mapping failure in rpcrdma_prepare_send_sges() runs rpcrdma_sendctx_cancel(), which DMA-unmaps the sendctx and clears sc_req without touching rl_kref. The sendctx ring walks in rpcrdma_sendctx_put_locked() and rpcrdma_sendctxs_destroy() skip entries with sc_req == NULL, so a burst of -EIO marshal failures cannot hold reqs off rb_send_bufs. - The release callback re-arms rl_kref so the next consumer enters with the invariant satisfied. Replies now complete the RPC directly. rpcrdma_reply_handler() calls rpcrdma_complete_rqst() in place of kref_put on the non-LocalInv branch. The LocalInv branch already completes the RPC from frwr_unmap_async() and is unaffected. Because Send-side references can now outlive RPC completion, connection teardown drains sendctx entries whose unsignaled Sends never had a later signaled completion to walk the ring. rpcrdma_sendctxs_destroy() walks the active range and runs rpcrdma_sendctx_unmap() on each entry with a non-NULL sc_req before the request buffers are reset, and is moved ahead of rpcrdma_reqs_reset() in rpcrdma_xprt_disconnect() so the reqs are still in their pre-reset state when the Send-side refs are released. The drain creates a teardown-ordering hazard on the backchannel path. With the new lifetime, releasing a bc_prealloc req from rpcrdma_req_release() re-adds it to bc_pa_list. The disconnect in xprt_rdma_destroy() runs after xprt_destroy_backchannel() has already emptied bc_pa_list, so the drained reqs would otherwise leak. xprt_rdma_destroy() now runs xprt_rdma_bc_destroy(xprt, 0) a second time after the disconnect to reclaim them.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel 5.3版本存在安全漏洞，该漏洞源于xprtrdma中rl_kref引用计数管理不当，可能导致请求在硬件仍读取发送缓冲区时被释放，造成释放后重用。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 0ab115237025f5e379620bbcd56a02697d07b002 ~ 740975054a1970c0cf15f70ac39724a064f45847 -
Linux Linux 5.3 -

II. Public POCs for CVE-2026-72473

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III. Intelligence Information for CVE-2026-72473

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Patches & Fixes for CVE-2026-72473 (6)

Same Patch Batch · Linux · 2026-08-15 · 845 CVEs total

CVE-2026-72421 10.0 CRITICAL ipv4: fib: Don't ignore error route in local/main tables.
CVE-2026-74279 10.0 CRITICAL crypto: cavium/cpt - fix DMA cleanup using wrong loop index
CVE-2026-72408 10.0 CRITICAL geneve: gate GRO hint in geneve_gro_complete() on gs->gro_hint
CVE-2026-72407 10.0 CRITICAL geneve: validate inner network offset in geneve_gro_complete()
CVE-2026-74309 10.0 CRITICAL vdpa/octeon_ep: fix IRQ-to-ring mapping in interrupt handler
CVE-2026-74280 10.0 CRITICAL crypto: marvell/octeontx - fix DMA cleanup using wrong loop index
CVE-2026-74475 10.0 CRITICAL vxlan: use neigh_ha_snapshot() in route_shortcircuit()
CVE-2026-72493 9.9 CRITICAL net: serialize netif_running() check in enqueue_to_backlog()
CVE-2026-74361 9.8 CRITICAL nvme: fix FDP fdpcidx bounds check
CVE-2026-74268 9.8 CRITICAL tcp: clear sock_ops cb flags before force-closing a child socket
CVE-2026-72064 9.8 CRITICAL net: mana: Sync page pool RX frags for CPU
CVE-2026-72065 9.8 CRITICAL net: mana: Validate the packet length reported by the NIC
CVE-2026-72069 9.8 CRITICAL locking/rt: Fix the incorrect RCU protection in rt_spin_unlock()
CVE-2026-72185 9.8 CRITICAL ntfs: fix WARN_ON for resident attribute in ntfs_map_runlist_nolock()
CVE-2026-72249 9.8 CRITICAL netfilter: flowtable: use dst in this direction when pushing IPIP header
CVE-2026-72494 9.8 CRITICAL RDMA/irdma: Replace waitqueue and flag with completion
CVE-2026-72248 9.8 CRITICAL netfilter: flowtable: support IPIP tunnel with direct xmit
CVE-2026-72491 9.8 CRITICAL net/9p: fix race condition on rdma->state in trans_rdma.c
CVE-2026-72251 9.8 CRITICAL netfilter: nf_nat_sip: reload possible stale data pointer
CVE-2026-74480 9.8 CRITICAL net: bridge: stop fast-leave after deleting a port group

Showing top 20 of 845 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

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