7.5
HIGH CVSS 3.1
CVE-2026-64281
svcrdma: wake sq waiters when the transport closes
Description

In the Linux kernel, the following vulnerability has been resolved: svcrdma: wake sq waiters when the transport closes Threads parked in svc_rdma_sq_wait() on sc_sq_ticket_wait or sc_send_wait can hang indefinitely in TASK_UNINTERRUPTIBLE state across transport teardown, pinning svc_xprt references and blocking svc_rdma_free(). The close path sets XPT_CLOSE before invoking xpo_detach and both wait_event predicates include an XPT_CLOSE term, but the predicates are re-evaluated only on wakeup. sc_sq_ticket_wait has no completion-driven wake path; it is advanced solely by the chained ticket handoff inside svc_rdma_sq_wait() itself. Without an explicit wake at close, parked threads never observe XPT_CLOSE, hold their svc_xprt_get reference forever, and svc_rdma_free() blocks on xpt_ref dropping to zero. Two close entry points reach this transport. Local teardown runs svc_rdma_detach() from svc_handle_xprt() -> svc_delete_xprt() -> xpo_detach() on a worker thread. A remote disconnect arrives at svc_rdma_cma_handler(), which calls svc_xprt_deferred_close(): that sets XPT_CLOSE and enqueues the transport but does not access either RDMA waitqueue, so a worker already parked in svc_rdma_sq_wait() never re-evaluates its predicate. With every worker parked on this transport, no thread is available to run the local teardown either, and the wake site there is unreachable. Introduce svc_rdma_xprt_deferred_close(), a thin svcrdma wrapper that calls svc_xprt_deferred_close() and then wakes both sc_sq_ticket_wait and sc_send_wait. Convert the svcrdma producers that called svc_xprt_deferred_close() directly: svc_rdma_cma_handler(), qp_event_handler(), svc_rdma_post_send_err(), svc_rdma_wc_send(), the sendto drop path, the rw completion error paths, and the recvfrom flush and read-list error paths. Wake both waitqueues from svc_rdma_detach() as well. The synchronous svc_xprt_close() path (backchannel ENOTCONN, device removal via svc_rdma_xprt_done) reaches detach without flowing through svc_xprt_deferred_close() and therefore does not invoke the new helper. [ cel: add svc_rdma_xprt_deferred_close() to complete the fix ]

INFO

Published Date :

July 25, 2026, 10:17 a.m.

Last Modified :

Aug. 17, 2026, 5:17 a.m.

Remotely Exploit :

Yes !

Source :

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

The following products are affected by CVE-2026-64281 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
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 HIGH 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
Introduce a wrapper function to wake wait queues during transport teardown.
  • Introduce svc_rdma_xprt_deferred_close() wrapper.
  • Wake wait queues in svc_rdma_sq_wait() and sc_send_wait.
  • Convert direct calls to svc_xprt_deferred_close().
  • Wake waitqueues from svc_rdma_detach() as well.
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-2026-64281.

URL Resource
https://git.kernel.org/stable/c/40eedc4253dbda0b29b7961200534dfcecb48ace Patch
https://git.kernel.org/stable/c/e5248a7426030db1e126363f72afdb3b71339a5c Patch
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-64281 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-2026-64281 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-2026-64281 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-64281 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
    Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'ccc89b9d1ed233349cfe8d87b842e7351b74d8de', 'lessThan': '40eedc4253dbda0b29b7961200534dfcecb48ace', 'versionType': 'git'}, {'status': 'affected', 'version': 'ccc89b9d1ed233349cfe8d87b842e7351b74d8de', 'lessThan': 'e5248a7426030db1e126363f72afdb3b71339a5c', 'versionType': 'git'}], 'programFiles': ['include/linux/sunrpc/svc_rdma.h', 'net/sunrpc/xprtrdma/svc_rdma_recvfrom.c', 'net/sunrpc/xprtrdma/svc_rdma_rw.c', 'net/sunrpc/xprtrdma/svc_rdma_sendto.c', 'net/sunrpc/xprtrdma/svc_rdma_transport.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '7.1'}, {'status': 'unaffected', 'version': '0', 'lessThan': '7.1', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '7.1.4', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['include/linux/sunrpc/svc_rdma.h', 'net/sunrpc/xprtrdma/svc_rdma_recvfrom.c', 'net/sunrpc/xprtrdma/svc_rdma_rw.c', 'net/sunrpc/xprtrdma/svc_rdma_sendto.c', 'net/sunrpc/xprtrdma/svc_rdma_transport.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'ccc89b9d1ed233349cfe8d87b842e7351b74d8de', 'lessThan': '40eedc4253dbda0b29b7961200534dfcecb48ace', 'versionType': 'git'}, {'status': 'affected', 'version': 'ccc89b9d1ed233349cfe8d87b842e7351b74d8de', 'lessThan': 'e5248a7426030db1e126363f72afdb3b71339a5c', 'versionType': 'git'}], 'programFiles': ['include/linux/sunrpc/svc_rdma.h', 'net/sunrpc/xprtrdma/svc_rdma_recvfrom.c', 'net/sunrpc/xprtrdma/svc_rdma_rw.c', 'net/sunrpc/xprtrdma/svc_rdma_sendto.c', 'net/sunrpc/xprtrdma/svc_rdma_transport.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '7.1'}, {'status': 'unaffected', 'version': '0', 'lessThan': '7.1', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '7.1.4', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['include/linux/sunrpc/svc_rdma.h', 'net/sunrpc/xprtrdma/svc_rdma_recvfrom.c', 'net/sunrpc/xprtrdma/svc_rdma_rw.c', 'net/sunrpc/xprtrdma/svc_rdma_sendto.c', 'net/sunrpc/xprtrdma/svc_rdma_transport.c'], 'defaultStatus': 'affected'}]
  • Initial Analysis by [email protected]

    Aug. 13, 2026

    Action Type Old Value New Value
    Added CWE NVD-CWE-noinfo
    Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 7.1 up to (excluding) 7.1.4
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/40eedc4253dbda0b29b7961200534dfcecb48ace Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/e5248a7426030db1e126363f72afdb3b71339a5c Types: Patch
  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Jul. 27, 2026

    Action Type Old Value New Value
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Jul. 25, 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': 'ccc89b9d1ed233349cfe8d87b842e7351b74d8de', 'lessThan': '40eedc4253dbda0b29b7961200534dfcecb48ace', 'versionType': 'git'}, {'status': 'affected', 'version': 'ccc89b9d1ed233349cfe8d87b842e7351b74d8de', 'lessThan': 'e5248a7426030db1e126363f72afdb3b71339a5c', 'versionType': 'git'}], 'programFiles': ['include/linux/sunrpc/svc_rdma.h', 'net/sunrpc/xprtrdma/svc_rdma_recvfrom.c', 'net/sunrpc/xprtrdma/svc_rdma_rw.c', 'net/sunrpc/xprtrdma/svc_rdma_sendto.c', 'net/sunrpc/xprtrdma/svc_rdma_transport.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '7.1'}, {'status': 'unaffected', 'version': '0', 'lessThan': '7.1', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '7.1.4', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['include/linux/sunrpc/svc_rdma.h', 'net/sunrpc/xprtrdma/svc_rdma_recvfrom.c', 'net/sunrpc/xprtrdma/svc_rdma_rw.c', 'net/sunrpc/xprtrdma/svc_rdma_sendto.c', 'net/sunrpc/xprtrdma/svc_rdma_transport.c'], 'defaultStatus': 'affected'}]
    Added Description In the Linux kernel, the following vulnerability has been resolved: svcrdma: wake sq waiters when the transport closes Threads parked in svc_rdma_sq_wait() on sc_sq_ticket_wait or sc_send_wait can hang indefinitely in TASK_UNINTERRUPTIBLE state across transport teardown, pinning svc_xprt references and blocking svc_rdma_free(). The close path sets XPT_CLOSE before invoking xpo_detach and both wait_event predicates include an XPT_CLOSE term, but the predicates are re-evaluated only on wakeup. sc_sq_ticket_wait has no completion-driven wake path; it is advanced solely by the chained ticket handoff inside svc_rdma_sq_wait() itself. Without an explicit wake at close, parked threads never observe XPT_CLOSE, hold their svc_xprt_get reference forever, and svc_rdma_free() blocks on xpt_ref dropping to zero. Two close entry points reach this transport. Local teardown runs svc_rdma_detach() from svc_handle_xprt() -> svc_delete_xprt() -> xpo_detach() on a worker thread. A remote disconnect arrives at svc_rdma_cma_handler(), which calls svc_xprt_deferred_close(): that sets XPT_CLOSE and enqueues the transport but does not access either RDMA waitqueue, so a worker already parked in svc_rdma_sq_wait() never re-evaluates its predicate. With every worker parked on this transport, no thread is available to run the local teardown either, and the wake site there is unreachable. Introduce svc_rdma_xprt_deferred_close(), a thin svcrdma wrapper that calls svc_xprt_deferred_close() and then wakes both sc_sq_ticket_wait and sc_send_wait. Convert the svcrdma producers that called svc_xprt_deferred_close() directly: svc_rdma_cma_handler(), qp_event_handler(), svc_rdma_post_send_err(), svc_rdma_wc_send(), the sendto drop path, the rw completion error paths, and the recvfrom flush and read-list error paths. Wake both waitqueues from svc_rdma_detach() as well. The synchronous svc_xprt_close() path (backchannel ENOTCONN, device removal via svc_rdma_xprt_done) reaches detach without flowing through svc_xprt_deferred_close() and therefore does not invoke the new helper. [ cel: add svc_rdma_xprt_deferred_close() to complete the fix ]
    Added Reference https://git.kernel.org/stable/c/40eedc4253dbda0b29b7961200534dfcecb48ace
    Added Reference https://git.kernel.org/stable/c/e5248a7426030db1e126363f72afdb3b71339a5c
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.