{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-72466", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-09T03:40:39.933Z", "datePublished": "2026-08-15T05:57:09.847Z", "dateUpdated": "2026-08-17T05:44:32.887Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:44:32.887Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxprtrdma: Fix bcall rep leak and unbounded peek\n\nrpcrdma_is_bcall() decodes a reply's first words to decide whether\nthe frame is a backchannel call. Two issues in that decode path\nlet a short or malformed reply leak the receive buffer and drain\nthe Receive queue.\n\nFirst, the speculative peek\n\n p = xdr_inline_decode(xdr, 0);\n /* five p++ reads follow */\n\nasks xdr_inline_decode() for zero bytes, which returns xdr->p\nwithout consulting xdr->end. The five subsequent __be32 reads can\nthen walk up to 20 bytes past the wire payload into stale regbuf\ncontents and misclassify the reply as a backchannel call.\n\nSecond, after the post-peek\n\n p = xdr_inline_decode(xdr, 3 * sizeof(*p));\n if (unlikely(!p))\n return true;\n\nthe short-header arm returns true without calling\nrpcrdma_bc_receive_call(). The contract with the caller is that a\ntrue return transfers ownership of rep to the backchannel path:\n\n rpcrdma_reply_handler()\n if (rpcrdma_is_bcall(r_xprt, rep))\n return; /* bare return, skips out_post */\n ...\n out_post:\n rpcrdma_post_recvs(r_xprt, credits + ...);\n\nBecause rpcrdma_bc_receive_call() never ran, no one took rep, but\nrpcrdma_reply_handler still bare-returns past rpcrdma_rep_put()\nand rpcrdma_post_recvs(). The rep, with its persistently\nDMA-mapped receive buffer, is orphaned on rb_all_reps and freed\nonly at transport teardown. This completion reposts nothing, so\nits slot is reclaimed only when a later forward-channel reply\nreaches out_post and rpcrdma_post_recvs() allocates a fresh rep to\nbackfill; absent that traffic the Receive queue drains and the\npeer's Sends draw RNR NAKs.\n\nFix by consulting xdr->end after the zero-length peek so the five\n__be32 reads cannot run unless 20 bytes of wire payload remain. A\nbyte-precise comparison against xdr->end is required because a\nnon-4-aligned receive rounds the stream's word count up past the\ntrue payload. Also return false from the short-header arm so the\nreply falls through the normal out_norqst cleanup chain\n(rpcrdma_rep_put() plus rpcrdma_post_recvs())." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - The bug is reached when a remote RDMA peer's inbound message completes in rpcrdma_wc_receive() and rpcrdma_reply_handler() decodes it; a malicious or compromised NFS-over-RDMA server can send crafted short rdma_msg replies over the established RPC/RDMA connection without local access.\nAC:L - On an active NFSv4.1+ RPC/RDMA session the attacker fully controls inbound replies and can repeatedly send short/malformed rdma_msg frames to hit the zero-length peek and short-header return-true paths, reliably leaking receive buffers and draining the Receive queue.\nPR:N - Exploitation requires only network reachability as the connected RDMA/RPC peer (e.g., a malicious NFS server); no local account, mount privileges, or namespaced capabilities on the victim NFS client are needed to deliver the malformed RDMA replies.\nUI:N - Once an NFS-over-RDMA mount and NFSv4.1 backchannel session exist, triggering the flaw needs no additional victim action beyond the attacker sending malicious RDMA receive payloads during normal client-server communication.\nS:U - The vulnerability and its impact remain within the NFS client's kernel SUNRPC/xprtrdma transport context; it does not cross a VM, container, or IOMMU security boundary to affect other authorities.\nC:H - xdr_inline_decode(xdr,0) permits up to five subsequent __be32 reads past the wire payload into stale receive-buffer contents, an out-of-bounds read that can misclassify replies and expose remnants of prior RPC/NFS data to unintended processing paths.\nI:H - Stale-buffer-assisted misclassification can treat a forward-channel reply as a backchannel RPC_CALL, a type confusion that routes attacker-influenced bytes into rpcrdma_bc_receive_call()/NFSv4 callback handling and can corrupt client session state.\nA:H - Each successful trigger orphans a DMA-mapped rpcrdma_rep and skips rpcrdma_post_recvs(), monotonically draining the RDMA Receive queue until the peer gets RNR NAKs and the NFS-over-RDMA connection becomes unusable, enabling sustained remote denial of 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": "41c8f70f5a3db7e06179186b6525fd9ee1d7d314", "lessThan": "0cee8f9c3b14bd6dee9c4310090a7f45b89b834f", "status": "affected", "versionType": "git" }, { "version": "41c8f70f5a3db7e06179186b6525fd9ee1d7d314", "lessThan": "7afc2f8d2fd9394724df9eaf22ce7a71029a5fba", "status": "affected", "versionType": "git" }, { "version": "41c8f70f5a3db7e06179186b6525fd9ee1d7d314", "lessThan": "88b5346284a184a6b7d019912232a571d672d3e3", "status": "affected", "versionType": "git" }, { "version": "41c8f70f5a3db7e06179186b6525fd9ee1d7d314", "lessThan": "07aa506436be7634e381e1e1f6d0efa9efc81ecc", "status": "affected", "versionType": "git" }, { "version": "41c8f70f5a3db7e06179186b6525fd9ee1d7d314", "lessThan": "d7a2870dde3bb09d51d6b9c877642996ad6b92dd", "status": "affected", "versionType": "git" }, { "version": "41c8f70f5a3db7e06179186b6525fd9ee1d7d314", "lessThan": "118a16a18c59f7ad8084b2d13988839b669fca10", "status": "affected", "versionType": "git" }, { "version": "41c8f70f5a3db7e06179186b6525fd9ee1d7d314", "lessThan": "c7653d5cebc8492c77ec0415b5e9c0fb3e644bc6", "status": "affected", "versionType": "git" } ] }, { "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": "4.14", "status": "affected" }, { "version": "0", "lessThan": "4.14", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.212", "lessThanOrEqual": "5.15.*", "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": "4.14", "versionEndExcluding": "5.15.212" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "6.1.178" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "6.12.97" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/0cee8f9c3b14bd6dee9c4310090a7f45b89b834f" }, { "url": "https://git.kernel.org/stable/c/7afc2f8d2fd9394724df9eaf22ce7a71029a5fba" }, { "url": "https://git.kernel.org/stable/c/88b5346284a184a6b7d019912232a571d672d3e3" }, { "url": "https://git.kernel.org/stable/c/07aa506436be7634e381e1e1f6d0efa9efc81ecc" }, { "url": "https://git.kernel.org/stable/c/d7a2870dde3bb09d51d6b9c877642996ad6b92dd" }, { "url": "https://git.kernel.org/stable/c/118a16a18c59f7ad8084b2d13988839b669fca10" }, { "url": "https://git.kernel.org/stable/c/c7653d5cebc8492c77ec0415b5e9c0fb3e644bc6" } ], "title": "xprtrdma: Fix bcall rep leak and unbounded peek", "x_generator": { "engine": "bippy-1.2.0" } } } }