GHSA-6MFM-2HG9-7GWW
Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-17 06:33In 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]
{
"affected": [],
"aliases": [
"CVE-2026-72222"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-15T06:21:41Z",
"severity": "CRITICAL"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsunrpc: pin svc_xprt across the asynchronous TLS handshake callback\n\nsvc_tcp_handshake() stores the raw svc_xprt pointer in\ntls_handshake_args.ta_data and submits the request through\ntls_server_hello_x509(). The handshake core takes only\nsock_hold(req-\u003ehr_sk); nothing references the embedding struct\nsvc_sock that svc_tcp_handshake_done() reaches via container_of().\n\nTwo close races leave the in-flight callback writing through a freed\nsvc_sock. svc_sock_free() calls tls_handshake_cancel() and discards\nits return value: a false return means handshake_complete() has\nalready set HANDSHAKE_F_REQ_COMPLETED but hp_done() may not have\nfinished, yet svc_sock_free() proceeds to kfree(svsk). The\ncancel-loser fall-through inside svc_tcp_handshake() itself produces\nthe same window: when wait_for_completion_interruptible_timeout()\nreturns \u003c= 0 (timeout or signal) and tls_handshake_cancel() returns\nfalse, the function does not drain, returns, and svc_handle_xprt()\ncalls svc_xprt_received(), which clears XPT_BUSY and can drop the\nlast reference. A concurrent close then runs svc_sock_free() while\nsvc_tcp_handshake_done() is still updating xpt_flags and walking\nsvsk-\u003esk_handshake_done.\n\nThe corruption surfaces as set_bit/clear_bit RMW into the freed\nxpt_flags slab slot and as complete_all() walking and writing the\nfreed wait_queue_head_t list embedded in sk_handshake_done -- a\nslab-corruption primitive, not a benign read. The path is reachable\non any TLS-enabled NFS server whenever a connection close overlaps\nthe tlshd downcall delivery window; the interruptible wait means\nsignal delivery suffices, not just SVC_HANDSHAKE_TO expiry.\n\nTake svc_xprt_get(xprt) immediately before tls_server_hello_x509()\nso the in-flight callback owns its own reference. Release it on the\ntwo edges where the callback is guaranteed not to fire -- submission\nfailure from tls_server_hello_x509() and a successful\ntls_handshake_cancel() -- and at the tail of\nsvc_tcp_handshake_done() after complete_all().\n\n[cel: rewrote commit message to describe the actual change]",
"id": "GHSA-6mfm-2hg9-7gww",
"modified": "2026-08-17T06:33:17Z",
"published": "2026-08-15T06:32:16Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72222"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/083e9c2ec7e8bb13b79c9fd7b337abdd758ecc5f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2d4f97d13fff91e0bc539216be88b884b544d49f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3f9ee75a97a769be258784c22b89657acb5ed9bd"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4f988f3a2808fb659f3880c282041ff067acad78"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f3b55945dd99f29d83e1965d0141040a35262346"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.