{"id":"CVE-2026-72466","title":"xprtrdma: Fix bcall rep leak and unbounded peek","summary":"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 …","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 41c8f70f5a3db7e06179186b6525fd9ee1d7d314 < 0cee8f9c3b14bd6dee9c4310090a7f45b89b834f","Linux >= 41c8f70f5a3db7e06179186b6525fd9ee1d7d314 < 7afc2f8d2fd9394724df9eaf22ce7a71029a5fba","Linux >= 41c8f70f5a3db7e06179186b6525fd9ee1d7d314 < 88b5346284a184a6b7d019912232a571d672d3e3","Linux >= 41c8f70f5a3db7e06179186b6525fd9ee1d7d314 < 07aa506436be7634e381e1e1f6d0efa9efc81ecc","Linux >= 41c8f70f5a3db7e06179186b6525fd9ee1d7d314 < d7a2870dde3bb09d51d6b9c877642996ad6b92dd","Linux >= 41c8f70f5a3db7e06179186b6525fd9ee1d7d314 < 118a16a18c59f7ad8084b2d13988839b669fca10","Linux >= 41c8f70f5a3db7e06179186b6525fd9ee1d7d314 < c7653d5cebc8492c77ec0415b5e9c0fb3e644bc6","Linux 4.14"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"total","timestamp":"2026-10-16T18:50:23.646833Z"},"published":"2026-08-15","updated":"2026-10-16","sourceUpdated":"2026-10-16T18:55:25.296Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72466","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"}],"tags":["cve.org"],"epss":0.00738,"epssPercentile":0.53608,"ingestedAt":"2026-10-16T19:46:24.393Z","slug":"CVE-2026-72466","body":"## Overview\n\nIn 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()).\n\n## Affected\n\n- `Linux >= 41c8f70f5a3db7e06179186b6525fd9ee1d7d314 < 0cee8f9c3b14bd6dee9c4310090a7f45b89b834f`\n- `Linux >= 41c8f70f5a3db7e06179186b6525fd9ee1d7d314 < 7afc2f8d2fd9394724df9eaf22ce7a71029a5fba`\n- `Linux >= 41c8f70f5a3db7e06179186b6525fd9ee1d7d314 < 88b5346284a184a6b7d019912232a571d672d3e3`\n- `Linux >= 41c8f70f5a3db7e06179186b6525fd9ee1d7d314 < 07aa506436be7634e381e1e1f6d0efa9efc81ecc`\n- `Linux >= 41c8f70f5a3db7e06179186b6525fd9ee1d7d314 < d7a2870dde3bb09d51d6b9c877642996ad6b92dd`\n- `Linux >= 41c8f70f5a3db7e06179186b6525fd9ee1d7d314 < 118a16a18c59f7ad8084b2d13988839b669fca10`\n- `Linux >= 41c8f70f5a3db7e06179186b6525fd9ee1d7d314 < c7653d5cebc8492c77ec0415b5e9c0fb3e644bc6`\n- `Linux 4.14`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}