CVE-2026-72466: Software Security Vulnerability Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-7c5h-c675-2hvr",
  "modified" : "2026-08-17T06:33:31Z",
  "published" : "2026-08-15T06:32:25Z",
  "aliases" : [ "CVE-2026-72466" ],
  "details" : "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()).",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-72466"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/07aa506436be7634e381e1e1f6d0efa9efc81ecc"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/0cee8f9c3b14bd6dee9c4310090a7f45b89b834f"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/118a16a18c59f7ad8084b2d13988839b669fca10"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/7afc2f8d2fd9394724df9eaf22ce7a71029a5fba"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/88b5346284a184a6b7d019912232a571d672d3e3"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/c7653d5cebc8492c77ec0415b5e9c0fb3e644bc6"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/d7a2870dde3bb09d51d6b9c877642996ad6b92dd"
  } ],
  "database_specific" : {
    "cwe_ids" : [ ],
    "severity" : "CRITICAL",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-08-15T06:22:20Z"
  }
}