Skip to content
Heist/ feed
Critical

SUNRPC: pin upper rpc_clnt across the TLS connect_worker

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: SUNRPC: pin upper rpc_clnt across the TLS connect_worker The TLS connect path has a use-after-free: nothing pins the upper rpc_clnt across the delayed connect_worker. xs_connect() stores task->tk_client in sock_xprt::clnt as a raw pointer and queues the worker; for TLS-secured transports that worker is xs_tcp_tls_setup_socket(), which reads several fields out of the saved pointer (cl_timeout, cl_program, cl_prog, cl_vers, cl_cred, cl_stats) to construct the args for the inner handshake rpc_clnt. The xprt does not reference the rpc_clnt; the rpc_clnt references the xprt. xs_destroy() does cancel the connect_worker, but it runs only when the xprt's refcount drops to zero, which cannot happen until the rpc_clnt releases its cl_xprt reference in rpc_free_client_work(). When a TLS handshake fails fatally (for example, an mTLS mount whose client cert does not match the server), the connecting task is woken with -EACCES and exits, the mount caller invokes rpc_shutdown_client(), and the upper rpc_clnt is freed before the queued connect_worker fires. xs_tcp_tls_setup_socket() then dereferences the freed clnt, producing the refcount_t underflow Michael Nemanov reported. Take a reference on the upper rpc_clnt in xs_connect() for TLS transports via a new rpc_hold_client() helper, and drop it in the connect_worker's exit path with rpc_release_client(). The xprt_lock_connect() / xprt_unlock_connect() pairing already serial

Announced Source revision 1
Original source ↗

CVE-2026-72317

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-72317

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "75eb6af7acdf566c68d61e98e67ee2f235201c02",
        "lessThan": "79cd550f8c884523b604fbfa43eb02def74d6224",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "75eb6af7acdf566c68d61e98e67ee2f235201c02",
        "lessThan": "7a65b41b657b71d5a77861f47dd13eb4bc8e10d0",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "75eb6af7acdf566c68d61e98e67ee2f235201c02",
        "lessThan": "5b0427ba582d143a364301f825f4e32272f06d2d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "75eb6af7acdf566c68d61e98e67ee2f235201c02",
        "lessThan": "d49f6d098ed48775b9d27a9f9c5c220fdf76f102",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "75eb6af7acdf566c68d61e98e67ee2f235201c02",
        "lessThan": "46bc86c833956219bbfd246c1ffd832a479c5199",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "include/linux/sunrpc/clnt.h",
      "net/sunrpc/clnt.c",
      "net/sunrpc/xprtsock.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "6.5"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "6.5",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.6.145",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.97",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.40",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.5",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "include/linux/sunrpc/clnt.h",
      "net/sunrpc/clnt.c",
      "net/sunrpc/xprtsock.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-72317

Source reference: /cveMetadata/cveId

Publisher severity

critical

Source reference: /containers/cna/metrics

Event
#33019 · Revision 1
Added to Heist Feed
Publisher date
Read the original announcement