CVE-2026-72222: sunrpc: pin svc_xprt across the asynchronous TLS handshake callback
In the Linux kernel, the following vulnerability has been resolved:
sunrpc: pin svcxprt across the asynchronous TLS handshake callback
svctcphandshake() stores the raw svcxprt pointer in tlshandshakeargs.tadata and submits the request through tlsserverhellox509(). The handshake core takes only sockhold(req->hrsk); nothing references the embedding struct svcsock that svctcphandshakedone() reaches via containerof().
Two close races leave the in-flight callback writing through a freed svcsock. svcsockfree() calls tlshandshakecancel() and discards its return value: a false return means handshakecomplete() has already set HANDSHAKEFREQCOMPLETED but hpdone() may not have finished, yet svcsockfree() proceeds to kfree(svsk). The cancel-loser fall-through inside svctcphandshake() itself produces the same window: when waitforcompletioninterruptibletimeout() returns <= 0 (timeout or signal) and tlshandshakecancel() returns false, the function does not drain, returns, and svchandlexprt() calls svcxprtreceived(), which clears XPTBUSY and can drop the last reference. A concurrent close then runs svcsockfree() while svctcphandshakedone() is still updating xptflags and walking svsk->skhandshakedone.
The corruption surfaces as setbit/clearbit RMW into the freed xptflags slab slot and as completeall() walking and writing the freed waitqueueheadt list embedded in skhandshakedone -- 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 SVCHANDSHAKETO expiry.
Take svcxprtget(xprt) immediately before tlsserverhellox509() 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 tlsserverhellox509() and a successful tlshandshakecancel() -- and at the tail of svctcphandshakedone() after completeall().
[cel: rewrote commit message to describe the actual change]
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 6.8.0-147.147 - Upgrade
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ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 6.8.0-1071.79 - Upgrade
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ubuntu/linux-azure-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17~24.04.1 - Upgrade
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ubuntu/linux-azure-fde-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1016.16~24.04.1 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 6.8.0-1071.79 - Upgrade
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ubuntu/linux-gcp-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1013.13~24.04.1 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 6.8.0-1067.68 - Upgrade
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ubuntu/linux-lowlatencyto a version that resolves this vulnerability.Fixed in 6.8.0-147.147.1 - Upgrade
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ubuntu/linux-nvidia-tegrato a version that resolves this vulnerability.Fixed in 6.8.0-1035.38 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 6.8.0-1064.67 - Upgrade
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ubuntu/linux-oracle-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1012.12~24.04.1 - Upgrade
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ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-34.34.1~24.04.1 - Upgrade
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ubuntu/linux-bluefieldto a version that resolves this vulnerability.Fixed in 6.8.0-1033.38 - Upgrade
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ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 6.8.1-1062.63 - Upgrade
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ubuntu/linux-aws-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1067.70+fips1 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1013.13 - Upgrade
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ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-azure-fdeto a version that resolves this vulnerability.Fixed in 7.0.0-1016.16 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1013.13 - Upgrade
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ubuntu/linux-gketo a version that resolves this vulnerability.Fixed in 7.0.0-1007.8 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1014.14 - Upgrade
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ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1014.14 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1012.12 - Upgrade
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ubuntu/linux-raspito a version that resolves this vulnerability.Fixed in 7.0.0-1020.20 - Upgrade
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ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-34.34.1
Event History
Frequently Asked Questions
What is the severity of CVE-2026-72222?
CVE-2026-72222 has a risk score of 60, indicating a medium level of severity.
How do I fix CVE-2026-72222?
To fix CVE-2026-72222, upgrade to the latest version of the Linux kernel where this vulnerability has been resolved.
What impact does CVE-2026-72222 have on system security?
CVE-2026-72222 can potentially allow an attacker to exploit the TLS handshake process, leading to various security issues.
Where does CVE-2026-72222 occur?
CVE-2026-72222 occurs in the Linux kernel's sunrpc subsystem during the asynchronous TLS handshake callback.
Is CVE-2026-72222 related to TLS vulnerabilities?
Yes, CVE-2026-72222 involves a security issue during the TLS handshake process in the sunrpc implementation.