sunrpc: pin svc_xprt across the asynchronous TLS handshake callback

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-72222
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-15 06:21:41 UTC
Updated2026-08-17 06:18:23 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: sunrpc: pin svc_xprt across the asynchronous TLS handshake callback svc_tcp_handshake() stores the raw svc_xprt pointer in tls_handshake_args.ta_data and submits the request through tls_server_hello_x509(). The handshake core takes only sock_hold(req->hr_sk); nothing references the embedding struct svc_sock that svc_tcp_handshake_done() reaches via container_of(). Two close races leave the in-flight callback writing through a freed svc_sock. svc_sock_free() calls tls_handshake_cancel() and discards its return value: a false return means handshake_complete() has already set HANDSHAKE_F_REQ_COMPLETED but hp_done() may not have finished, yet svc_sock_free() proceeds to kfree(svsk). The cancel-loser fall-through inside svc_tcp_handshake() itself produces the same window: when wait_for_completion_interruptible_timeout() returns <= 0 (timeout or signal) and tls_handshake_cancel() returns false, the function does not drain, returns, and svc_handle_xprt() calls svc_xprt_received(), which clears XPT_BUSY and can drop the last reference. A concurrent close then runs svc_sock_free() while svc_tcp_handshake_done() is still updating xpt_flags and walking svsk->sk_handshake_done. The corruption surfaces as set_bit/clear_bit RMW into the freed xpt_flags slab slot and as complete_all() walking and writing the freed wait_queue_head_t list embedded in sk_handshake_done -- a slab-corruption primitive, not a benign read. The path is reachable on any TLS-enabled NFS server whenever a connection close overlaps the tlshd downcall delivery window; the interruptible wait means signal delivery suffices, not just SVC_HANDSHAKE_TO expiry. Take svc_xprt_get(xprt) immediately before tls_server_hello_x509() so the in-flight callback owns its own reference. Release it on the two edges where the callback is guaranteed not to fire -- submission failure from tls_server_hello_x509() and a successful tls_handshake_cancel() -- and at the tail of svc_tcp_handshake_done() after complete_all(). [cel: rewrote commit message to describe the actual change]

Risk And Classification

Primary CVSS: v3.1 9.8 CRITICAL from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.006260000 probability, percentile 0.470850000 (date 2026-08-17)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected b3cbf98e2fdf3cb147a95161560cd25987284330 f3b55945dd99f29d83e1965d0141040a35262346 git Not specified
CNA Linux Linux affected b3cbf98e2fdf3cb147a95161560cd25987284330 2d4f97d13fff91e0bc539216be88b884b544d49f git Not specified
CNA Linux Linux affected b3cbf98e2fdf3cb147a95161560cd25987284330 3f9ee75a97a769be258784c22b89657acb5ed9bd git Not specified
CNA Linux Linux affected b3cbf98e2fdf3cb147a95161560cd25987284330 083e9c2ec7e8bb13b79c9fd7b337abdd758ecc5f git Not specified
CNA Linux Linux affected b3cbf98e2fdf3cb147a95161560cd25987284330 4f988f3a2808fb659f3880c282041ff067acad78 git Not specified
CNA Linux Linux affected 6.4 Not specified
CNA Linux Linux unaffected 6.4 semver Not specified
CNA Linux Linux unaffected 6.6.145 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.97 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.40 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.5 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/f3b55945dd99f29d83e1965d0141040a35262346 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/083e9c2ec7e8bb13b79c9fd7b337abdd758ecc5f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/2d4f97d13fff91e0bc539216be88b884b544d49f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/3f9ee75a97a769be258784c22b89657acb5ed9bd 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/4f988f3a2808fb659f3880c282041ff067acad78 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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