{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-72464", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-09T03:40:39.933Z", "datePublished": "2026-08-15T05:57:08.080Z", "dateUpdated": "2026-08-17T05:44:30.706Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:44:30.706Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxprtrdma: Repost Receive buffers for malformed replies\n\nrpcrdma_wc_receive() decrements the transport's Receive count for\nevery completion before it dispatches a successful Receive to\nrpcrdma_reply_handler(). The handler must post a replacement\nReceive WR before returning unless ownership of the rep has moved\nelsewhere, as on the backchannel path.\n\nCommit 2ae50ad68cd7 (\"xprtrdma: Close window between waking RPC\nsenders and posting Receives\") moved the Receive refill out of\nrpcrdma_wc_receive(), where it had run ahead of every reply, into\nrpcrdma_reply_handler() so that the responder's credit grant could\nbe parsed before reposting. The bad-version and short-reply exits\nnever reach that refill: they recycle the rep and return without\ncalling rpcrdma_post_recvs().\n\nA remote peer can therefore drain the client's posted Receive\nqueue by sending a sustained stream of replies that are shorter\nthan the fixed transport header or that carry an unrecognized\nRPC/RDMA version. Each such reply consumes one posted Receive\nwithout replacing it. Once the queue empties, the peer's next\nSend finds no posted Receive and the transport stalls until\nreconnect.\n\nRoute both malformed-reply exits through the shared repost tail\nafter recycling the rep, refilling against buf->rb_credits, the\nmost recent accepted credit grant. Neither exit updates the\ncongestion window, so RPCs admitted under the previous grant\nremain in flight awaiting replies. A smaller refill target would\nlet a stream of malformed replies ratchet the posted Receive count\ndown to the batch floor while the congestion window still admits\nrb_credits RPCs; a burst of valid replies to those RPCs could then\noverrun the posted Receives, and because the client connects with\nrnr_retry_count of zero, a single RNR NAK terminates the\nconnection. Refilling against rb_credits also restores the target\nthat applied to malformed replies before commit 2ae50ad68cd7\n(\"xprtrdma: Close window between waking RPC senders and posting\nReceives\") when rpcrdma_post_recvs() computed it from rb_credits\ninternally. rb_credits is at least one from connection\nestablishment onward, so the repost path always keeps Receives\nposted." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - Malicious or compromised NFS/RDMA server sends malformed RPC reply messages over an established RDMA connection; the kernel client processes them in rpcrdma_wc_receive()/rpcrdma_reply_handler() without any local access.\nAC:L - Remote server reliably triggers the bug by streaming replies shorter than the fixed RPC/RDMA header or carrying an unrecognized version; each consumes a posted Receive without reposting a replacement.\nPR:N - Attacker needs no credentials on the victim host, only the ability to act as the connected RDMA peer (e.g., a malicious or compromised NFS server the client has mounted).\nUI:N - Exploitation requires only an active NFS-over-RDMA client session; no additional victim action is needed beyond an existing mount/connection used for normal I/O.\nS:U - Impact is confined to SunRPC/RDMA transport availability on the NFS client; it does not cross VM, container, or kernel/user security boundaries.\nC:N - No memory corruption or out-of-bounds access occurs; short or bad-version replies are detected during header decode and the buffer is recycled without disclosing kernel data.\nI:N - The flaw only fails to repost Receive buffers after malformed replies; it does not corrupt memory, alter RPC payloads, or enable arbitrary kernel writes.\nA:H - Sustained malformed replies drain all posted Receives, stalling the transport until reconnect; a burst of valid replies can trigger RNR NAK and disconnect (rnr_retry_count=0), denying NFS/RDMA service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sunrpc/xprtrdma/rpc_rdma.c" ], "versions": [ { "version": "2ae50ad68cd79224198b525f7bd645c9da98b6ff", "lessThan": "ef6fb8a5c521f1a07f85202d13e8f2898f247362", "status": "affected", "versionType": "git" }, { "version": "2ae50ad68cd79224198b525f7bd645c9da98b6ff", "lessThan": "4322fd9645ee769ad29ce5caea74a1cd9b17269d", "status": "affected", "versionType": "git" }, { "version": "2ae50ad68cd79224198b525f7bd645c9da98b6ff", "lessThan": "19fae02b272ee4bcdfb5db57f402d28f1697167a", "status": "affected", "versionType": "git" }, { "version": "2ae50ad68cd79224198b525f7bd645c9da98b6ff", "lessThan": "007b4da2f38dcc16a13265416f4ca9f179bab610", "status": "affected", "versionType": "git" }, { "version": "2ae50ad68cd79224198b525f7bd645c9da98b6ff", "lessThan": "d7c531ab477ae94fd03771d707fd29c787408039", "status": "affected", "versionType": "git" }, { "version": "2ae50ad68cd79224198b525f7bd645c9da98b6ff", "lessThan": "abc011ddaf1617e3e82d8a1e87daa7ddbfb9bac5", "status": "affected", "versionType": "git" }, { "version": "3791c5982ba1eebf2900ee7ca7b9a89619c26d54", "status": "affected", "versionType": "git" }, { "version": "5.4.13", "lessThan": "5.5", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sunrpc/xprtrdma/rpc_rdma.c" ], "versions": [ { "version": "5.5", "status": "affected" }, { "version": "0", "lessThan": "5.5", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.1.178" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.12.97" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "7.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4.13" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/ef6fb8a5c521f1a07f85202d13e8f2898f247362" }, { "url": "https://git.kernel.org/stable/c/4322fd9645ee769ad29ce5caea74a1cd9b17269d" }, { "url": "https://git.kernel.org/stable/c/19fae02b272ee4bcdfb5db57f402d28f1697167a" }, { "url": "https://git.kernel.org/stable/c/007b4da2f38dcc16a13265416f4ca9f179bab610" }, { "url": "https://git.kernel.org/stable/c/d7c531ab477ae94fd03771d707fd29c787408039" }, { "url": "https://git.kernel.org/stable/c/abc011ddaf1617e3e82d8a1e87daa7ddbfb9bac5" } ], "title": "xprtrdma: Repost Receive buffers for malformed replies", "x_generator": { "engine": "bippy-1.2.0" } } } }