{"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"}}}}