{"id":"CVE-2026-72464","revision":"6e59da0328ef4af8b726dfd9937c3873","records":[{"revision":"6e59da0328ef4af8b726dfd9937c3873","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-72464","aliases":[],"title":"xprtrdma: Repost Receive buffers for malformed replies","description":"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.","state":0,"publishedAt":"2026-08-15T05:57:08.08+00:00","modifiedAt":"2026-10-16T18:55:25.14+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/sunrpc/xprtrdma/rpc_rdma.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"2ae50ad68cd79224198b525f7bd645c9da98b6ff\",\n                            \"lessThan\": \"ef6fb8a5c521f1a07f85202d13e8f2898f247362\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"2ae50ad68cd79224198b525f7bd645c9da98b6ff\",\n                            \"lessThan\": \"4322fd9645ee769ad29ce5caea74a1cd9b17269d\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"2ae50ad68cd79224198b525f7bd645c9da98b6ff\",\n                            \"lessThan\": \"19fae02b272ee4bcdfb5db57f402d28f1697167a\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"2ae50ad68cd79224198b525f7bd645c9da98b6ff\",\n                            \"lessThan\": \"007b4da2f38dcc16a13265416f4ca9f179bab610\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"2ae50ad68cd79224198b525f7bd645c9da98b6ff\",\n                            \"lessThan\": \"d7c531ab477ae94fd03771d707fd29c787408039\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"2ae50ad68cd79224198b525f7bd645c9da98b6ff\",\n                            \"lessThan\": \"abc011ddaf1617e3e82d8a1e87daa7ddbfb9bac5\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3791c5982ba1eebf2900ee7ca7b9a89619c26d54\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"5.4.13\",\n                            \"lessThan\": \"5.5\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/sunrpc/xprtrdma/rpc_rdma.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"5.5\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"5.5\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.178\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.145\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.97\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.40\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.1.5\",\n                            \"lessThanOrEqual\": \"7.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/ef6fb8a5c521f1a07f85202d13e8f2898f247362","https://git.kernel.org/stable/c/4322fd9645ee769ad29ce5caea74a1cd9b17269d","https://git.kernel.org/stable/c/19fae02b272ee4bcdfb5db57f402d28f1697167a","https://git.kernel.org/stable/c/007b4da2f38dcc16a13265416f4ca9f179bab610","https://git.kernel.org/stable/c/d7c531ab477ae94fd03771d707fd29c787408039","https://git.kernel.org/stable/c/abc011ddaf1617e3e82d8a1e87daa7ddbfb9bac5"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72464","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-72464","identifiers":["CVE-2026-72464"]},"retained":false,"historicalAffected":[]}],"coverage":[]}