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9.8
CRITICAL CVSS 3.1
CVE-2026-72221
sunrpc: wait for in-flight TLS handshake callback when cancel loses race
Overview
Description

In the Linux kernel, the following vulnerability has been resolved: sunrpc: wait for in-flight TLS handshake callback when cancel loses race When wait_for_completion_interruptible_timeout() in svc_tcp_handshake() returns 0 (timeout) or -ERESTARTSYS (signal) and tls_handshake_cancel() then returns false, handshake_complete() has won the cancellation race: it has set HANDSHAKE_F_REQ_COMPLETED and is about to invoke svc_tcp_handshake_done(), but the callback's side effects on xpt_flags and on svsk->sk_handshake_done have not yet committed. The current code reads xpt_flags immediately to decide whether the session succeeded. Two races result. If the callback has executed set_bit(XPT_TLS_SESSION) but not yet clear_bit(XPT_HANDSHAKE), svc_tcp_handshake() sees a session, enqueues the transport, and returns. svc_xprt_received() then clears XPT_BUSY, a worker thread picks the transport up, the dispatcher in svc_handle_xprt() observes XPT_HANDSHAKE still set, and xpo_handshake is invoked a second time. That svc_tcp_handshake() calls init_completion(&svsk->sk_handshake_done) while the original callback concurrently calls complete_all() on it, corrupting the embedded swait_queue. If the callback has set HANDSHAKE_F_REQ_COMPLETED but not yet entered svc_tcp_handshake_done(), svc_tcp_handshake() reads XPT_TLS_SESSION as clear and tears the connection down even though the handshake is about to succeed. Wait for the callback to commit before inspecting xpt_flags. The completion is guaranteed to fire because handshake_complete() invokes svc_tcp_handshake_done() unconditionally once it has set HANDSHAKE_F_REQ_COMPLETED.

Details
INFO

Published Date :

Aug. 15, 2026, 6:21 a.m.

Last Modified :

Aug. 17, 2026, 6:18 a.m.

Remotely Exploit :

Yes !

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Impact
Affected Products

The following products are affected by CVE-2026-72221 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
: Total Affected Vendor : 1 | Products : 1
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 CRITICAL 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
Ensure handshake callback completes before checking flags to prevent races.
  • Wait for handshake callback completion.
  • Inspect xpt_flags after completion.
  • Apply relevant security patches.
  • Review kernel handling of concurrent operations.
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-72221.

URL Resource
https://git.kernel.org/stable/c/0d8ceb39884148dc7a2fdf71e1cac5961ed1d2b9
https://git.kernel.org/stable/c/65b23bec1fca6e9ebdc3e6041ebf8c6ab074141b
https://git.kernel.org/stable/c/a4f878e8ecd729ccf2e50993444e217583adeace
https://git.kernel.org/stable/c/d00e32f84ca1a77cb67a3fbf59f58dada95f5a21
https://git.kernel.org/stable/c/e0f4691d42a54d359d8b64509fd9ab938d4f2a33
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-72221 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-72221 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-72221 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-72221 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Aug. 17, 2026

    Action Type Old Value New Value
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'b3cbf98e2fdf3cb147a95161560cd25987284330', 'lessThan': '0d8ceb39884148dc7a2fdf71e1cac5961ed1d2b9', 'versionType': 'git'}, {'status': 'affected', 'version': 'b3cbf98e2fdf3cb147a95161560cd25987284330', 'lessThan': 'e0f4691d42a54d359d8b64509fd9ab938d4f2a33', 'versionType': 'git'}, {'status': 'affected', 'version': 'b3cbf98e2fdf3cb147a95161560cd25987284330', 'lessThan': '65b23bec1fca6e9ebdc3e6041ebf8c6ab074141b', 'versionType': 'git'}, {'status': 'affected', 'version': 'b3cbf98e2fdf3cb147a95161560cd25987284330', 'lessThan': 'a4f878e8ecd729ccf2e50993444e217583adeace', 'versionType': 'git'}, {'status': 'affected', 'version': 'b3cbf98e2fdf3cb147a95161560cd25987284330', 'lessThan': 'd00e32f84ca1a77cb67a3fbf59f58dada95f5a21', 'versionType': 'git'}], 'programFiles': ['net/sunrpc/svcsock.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.4'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.4', '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-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/sunrpc/svcsock.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'b3cbf98e2fdf3cb147a95161560cd25987284330', 'lessThan': '0d8ceb39884148dc7a2fdf71e1cac5961ed1d2b9', 'versionType': 'git'}, {'status': 'affected', 'version': 'b3cbf98e2fdf3cb147a95161560cd25987284330', 'lessThan': 'e0f4691d42a54d359d8b64509fd9ab938d4f2a33', 'versionType': 'git'}, {'status': 'affected', 'version': 'b3cbf98e2fdf3cb147a95161560cd25987284330', 'lessThan': '65b23bec1fca6e9ebdc3e6041ebf8c6ab074141b', 'versionType': 'git'}, {'status': 'affected', 'version': 'b3cbf98e2fdf3cb147a95161560cd25987284330', 'lessThan': 'a4f878e8ecd729ccf2e50993444e217583adeace', 'versionType': 'git'}, {'status': 'affected', 'version': 'b3cbf98e2fdf3cb147a95161560cd25987284330', 'lessThan': 'd00e32f84ca1a77cb67a3fbf59f58dada95f5a21', 'versionType': 'git'}], 'programFiles': ['net/sunrpc/svcsock.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.4'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.4', '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': ['net/sunrpc/svcsock.c'], 'defaultStatus': 'affected'}]
  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Aug. 15, 2026

    Action Type Old Value New Value
    Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'b3cbf98e2fdf3cb147a95161560cd25987284330', 'lessThan': '0d8ceb39884148dc7a2fdf71e1cac5961ed1d2b9', 'versionType': 'git'}, {'status': 'affected', 'version': 'b3cbf98e2fdf3cb147a95161560cd25987284330', 'lessThan': 'e0f4691d42a54d359d8b64509fd9ab938d4f2a33', 'versionType': 'git'}, {'status': 'affected', 'version': 'b3cbf98e2fdf3cb147a95161560cd25987284330', 'lessThan': '65b23bec1fca6e9ebdc3e6041ebf8c6ab074141b', 'versionType': 'git'}, {'status': 'affected', 'version': 'b3cbf98e2fdf3cb147a95161560cd25987284330', 'lessThan': 'a4f878e8ecd729ccf2e50993444e217583adeace', 'versionType': 'git'}, {'status': 'affected', 'version': 'b3cbf98e2fdf3cb147a95161560cd25987284330', 'lessThan': 'd00e32f84ca1a77cb67a3fbf59f58dada95f5a21', 'versionType': 'git'}], 'programFiles': ['net/sunrpc/svcsock.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.4'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.4', '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-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/sunrpc/svcsock.c'], 'defaultStatus': 'affected'}]
    Added Description In the Linux kernel, the following vulnerability has been resolved: sunrpc: wait for in-flight TLS handshake callback when cancel loses race When wait_for_completion_interruptible_timeout() in svc_tcp_handshake() returns 0 (timeout) or -ERESTARTSYS (signal) and tls_handshake_cancel() then returns false, handshake_complete() has won the cancellation race: it has set HANDSHAKE_F_REQ_COMPLETED and is about to invoke svc_tcp_handshake_done(), but the callback's side effects on xpt_flags and on svsk->sk_handshake_done have not yet committed. The current code reads xpt_flags immediately to decide whether the session succeeded. Two races result. If the callback has executed set_bit(XPT_TLS_SESSION) but not yet clear_bit(XPT_HANDSHAKE), svc_tcp_handshake() sees a session, enqueues the transport, and returns. svc_xprt_received() then clears XPT_BUSY, a worker thread picks the transport up, the dispatcher in svc_handle_xprt() observes XPT_HANDSHAKE still set, and xpo_handshake is invoked a second time. That svc_tcp_handshake() calls init_completion(&svsk->sk_handshake_done) while the original callback concurrently calls complete_all() on it, corrupting the embedded swait_queue. If the callback has set HANDSHAKE_F_REQ_COMPLETED but not yet entered svc_tcp_handshake_done(), svc_tcp_handshake() reads XPT_TLS_SESSION as clear and tears the connection down even though the handshake is about to succeed. Wait for the callback to commit before inspecting xpt_flags. The completion is guaranteed to fire because handshake_complete() invokes svc_tcp_handshake_done() unconditionally once it has set HANDSHAKE_F_REQ_COMPLETED.
    Added Reference https://git.kernel.org/stable/c/0d8ceb39884148dc7a2fdf71e1cac5961ed1d2b9
    Added Reference https://git.kernel.org/stable/c/65b23bec1fca6e9ebdc3e6041ebf8c6ab074141b
    Added Reference https://git.kernel.org/stable/c/a4f878e8ecd729ccf2e50993444e217583adeace
    Added Reference https://git.kernel.org/stable/c/d00e32f84ca1a77cb67a3fbf59f58dada95f5a21
    Added Reference https://git.kernel.org/stable/c/e0f4691d42a54d359d8b64509fd9ab938d4f2a33
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
Base CVSS Score: 9.8
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