CVE-2026-72317 - Vulnerability Details

Vendors	Products
Linux	Linux Kernel

Link	Providers
https://git.kernel.org/stable/c/46bc86c833956219bbfd246c1ffd832a479c5199
https://git.kernel.org/stable/c/5b0427ba582d143a364301f825f4e32272f06d2d
https://git.kernel.org/stable/c/79cd550f8c884523b604fbfa43eb02def74d6224
https://git.kernel.org/stable/c/7a65b41b657b71d5a77861f47dd13eb4bc8e10d0
https://git.kernel.org/stable/c/d49f6d098ed48775b9d27a9f9c5c220fdf76f102

Type	Values Removed	Values Added
Weaknesses		CWE-416

Type	Values Removed	Values Added
Description		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 serialises xs_connect() with xs_tcp_tls_setup_socket(), so the take and release are balanced one-for-one. The non-TLS connect worker (xs_tcp_setup_socket) never reads sock_xprt::clnt, so leave that path alone and avoid the clnt-holds-xprt-holds-clnt cycle that would otherwise prevent xprt destruction.
Title		SUNRPC: pin upper rpc_clnt across the TLS connect_worker
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/46bc86c833956219bbfd246c1ffd832a479c5199 https://git.kernel.org/stable/c/5b0427ba582d143a364301f825f4e32272f06d2d https://git.kernel.org/stable/c/79cd550f8c884523b604fbfa43eb02def74d6224 https://git.kernel.org/stable/c/7a65b41b657b71d5a77861f47dd13eb4bc8e10d0 https://git.kernel.org/stable/c/d49f6d098ed48775b9d27a9f9c5c220fdf76f102

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-72317", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-09T03:40:39.919Z", "datePublished": "2026-08-15T05:55:31.022Z", "dateUpdated": "2026-08-15T05:55:31.022Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-15T05:55:31.022Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: pin upper rpc_clnt across the TLS connect_worker\n\nThe TLS connect path has a use-after-free: nothing pins the\nupper rpc_clnt across the delayed connect_worker. xs_connect()\nstores task->tk_client in sock_xprt::clnt as a raw pointer\nand queues the worker; for TLS-secured transports that worker\nis xs_tcp_tls_setup_socket(), which reads several fields out\nof the saved pointer (cl_timeout, cl_program, cl_prog,\ncl_vers, cl_cred, cl_stats) to construct the args for the\ninner handshake rpc_clnt.\n\nThe xprt does not reference the rpc_clnt; the rpc_clnt\nreferences the xprt. xs_destroy() does cancel the\nconnect_worker, but it runs only when the xprt's refcount\ndrops to zero, which cannot happen until the rpc_clnt\nreleases its cl_xprt reference in rpc_free_client_work().\nWhen a TLS handshake fails fatally (for example, an mTLS\nmount whose client cert does not match the server), the\nconnecting task is woken with -EACCES and exits, the mount\ncaller invokes rpc_shutdown_client(), and the upper rpc_clnt\nis freed before the queued connect_worker fires.\nxs_tcp_tls_setup_socket() then dereferences the freed clnt,\nproducing the refcount_t underflow Michael Nemanov reported.\n\nTake a reference on the upper rpc_clnt in xs_connect() for\nTLS transports via a new rpc_hold_client() helper, and drop\nit in the connect_worker's exit path with rpc_release_client().\nThe xprt_lock_connect() / xprt_unlock_connect() pairing\nalready serialises xs_connect() with xs_tcp_tls_setup_socket(),\nso the take and release are balanced one-for-one.\n\nThe non-TLS connect worker (xs_tcp_setup_socket) never reads\nsock_xprt::clnt, so leave that path alone and avoid the\nclnt-holds-xprt-holds-clnt cycle that would otherwise prevent\nxprt destruction."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["include/linux/sunrpc/clnt.h", "net/sunrpc/clnt.c", "net/sunrpc/xprtsock.c"], "versions": [{"version": "75eb6af7acdf566c68d61e98e67ee2f235201c02", "lessThan": "79cd550f8c884523b604fbfa43eb02def74d6224", "status": "affected", "versionType": "git"}, {"version": "75eb6af7acdf566c68d61e98e67ee2f235201c02", "lessThan": "7a65b41b657b71d5a77861f47dd13eb4bc8e10d0", "status": "affected", "versionType": "git"}, {"version": "75eb6af7acdf566c68d61e98e67ee2f235201c02", "lessThan": "5b0427ba582d143a364301f825f4e32272f06d2d", "status": "affected", "versionType": "git"}, {"version": "75eb6af7acdf566c68d61e98e67ee2f235201c02", "lessThan": "d49f6d098ed48775b9d27a9f9c5c220fdf76f102", "status": "affected", "versionType": "git"}, {"version": "75eb6af7acdf566c68d61e98e67ee2f235201c02", "lessThan": "46bc86c833956219bbfd246c1ffd832a479c5199", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["include/linux/sunrpc/clnt.h", "net/sunrpc/clnt.c", "net/sunrpc/xprtsock.c"], "versions": [{"version": "6.5", "status": "affected"}, {"version": "0", "lessThan": "6.5", "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-rc3", "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": "6.5", "versionEndExcluding": "6.6.145"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.5", "versionEndExcluding": "6.12.97"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.5", "versionEndExcluding": "6.18.40"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.5", "versionEndExcluding": "7.1.5"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.5", "versionEndExcluding": "7.2-rc3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/79cd550f8c884523b604fbfa43eb02def74d6224"}, {"url": "https://git.kernel.org/stable/c/7a65b41b657b71d5a77861f47dd13eb4bc8e10d0"}, {"url": "https://git.kernel.org/stable/c/5b0427ba582d143a364301f825f4e32272f06d2d"}, {"url": "https://git.kernel.org/stable/c/d49f6d098ed48775b9d27a9f9c5c220fdf76f102"}, {"url": "https://git.kernel.org/stable/c/46bc86c833956219bbfd246c1ffd832a479c5199"}], "title": "SUNRPC: pin upper rpc_clnt across the TLS connect_worker", "x_generator": {"engine": "bippy-1.2.0"}}}}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["include/linux/sunrpc/clnt.h", "net/sunrpc/clnt.c", "net/sunrpc/xprtsock.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "79cd550f8c884523b604fbfa43eb02def74d6224", "status": "affected", "version": "75eb6af7acdf566c68d61e98e67ee2f235201c02", "versionType": "git"}, {"lessThan": "7a65b41b657b71d5a77861f47dd13eb4bc8e10d0", "status": "affected", "version": "75eb6af7acdf566c68d61e98e67ee2f235201c02", "versionType": "git"}, {"lessThan": "5b0427ba582d143a364301f825f4e32272f06d2d", "status": "affected", "version": "75eb6af7acdf566c68d61e98e67ee2f235201c02", "versionType": "git"}, {"lessThan": "d49f6d098ed48775b9d27a9f9c5c220fdf76f102", "status": "affected", "version": "75eb6af7acdf566c68d61e98e67ee2f235201c02", "versionType": "git"}, {"lessThan": "46bc86c833956219bbfd246c1ffd832a479c5199", "status": "affected", "version": "75eb6af7acdf566c68d61e98e67ee2f235201c02", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["include/linux/sunrpc/clnt.h", "net/sunrpc/clnt.c", "net/sunrpc/xprtsock.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.5"}, {"lessThan": "6.5", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.145", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.97", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.40", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.5", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2-rc3", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: pin upper rpc_clnt across the TLS connect_worker\n\nThe TLS connect path has a use-after-free: nothing pins the\nupper rpc_clnt across the delayed connect_worker. xs_connect()\nstores task->tk_client in sock_xprt::clnt as a raw pointer\nand queues the worker; for TLS-secured transports that worker\nis xs_tcp_tls_setup_socket(), which reads several fields out\nof the saved pointer (cl_timeout, cl_program, cl_prog,\ncl_vers, cl_cred, cl_stats) to construct the args for the\ninner handshake rpc_clnt.\n\nThe xprt does not reference the rpc_clnt; the rpc_clnt\nreferences the xprt. xs_destroy() does cancel the\nconnect_worker, but it runs only when the xprt's refcount\ndrops to zero, which cannot happen until the rpc_clnt\nreleases its cl_xprt reference in rpc_free_client_work().\nWhen a TLS handshake fails fatally (for example, an mTLS\nmount whose client cert does not match the server), the\nconnecting task is woken with -EACCES and exits, the mount\ncaller invokes rpc_shutdown_client(), and the upper rpc_clnt\nis freed before the queued connect_worker fires.\nxs_tcp_tls_setup_socket() then dereferences the freed clnt,\nproducing the refcount_t underflow Michael Nemanov reported.\n\nTake a reference on the upper rpc_clnt in xs_connect() for\nTLS transports via a new rpc_hold_client() helper, and drop\nit in the connect_worker's exit path with rpc_release_client().\nThe xprt_lock_connect() / xprt_unlock_connect() pairing\nalready serialises xs_connect() with xs_tcp_tls_setup_socket(),\nso the take and release are balanced one-for-one.\n\nThe non-TLS connect worker (xs_tcp_setup_socket) never reads\nsock_xprt::clnt, so leave that path alone and avoid the\nclnt-holds-xprt-holds-clnt cycle that would otherwise prevent\nxprt destruction."}], "id": "CVE-2026-72317", "lastModified": "2026-08-15T06:22:04.620", "metrics": {}, "published": "2026-08-15T06:22:04.620", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/46bc86c833956219bbfd246c1ffd832a479c5199"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/5b0427ba582d143a364301f825f4e32272f06d2d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/79cd550f8c884523b604fbfa43eb02def74d6224"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/7a65b41b657b71d5a77861f47dd13eb4bc8e10d0"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d49f6d098ed48775b9d27a9f9c5c220fdf76f102"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

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