[CVE-2026-98072][MODERATE REGULAR] net/rds: use wq_has_sleeper() in release_in_xmit() [ Upstream

[CVE-2026-98072][MODERATE REGULAR] net/rds: use wq_has_sleeper() in release_in_xmit() [ Upstream

[AL-KERNEL]

CVE: CVE-2026-98072
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: net/rds: use wq_has_sleeper() in release_in_xmit() [ Upstream
Commit: ed7ee0cd0e136d02f87f13181b1a89880463c7e9
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ed7ee0cd0e136d02f87f13181b1a89880463c7e9
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98072
Analysis date: Sat, 26 Sep 2026 09:41:14 -0400
ActionableScore: 0
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO

Summary:
No one-sentence report phrase was found.

======================================================================
ABOUT THIS REPORT
======================================================================

The original Linux kernel CVE announcement for CVE-2026-98072 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98072

The original announcement does not normally provide a security severity
estimate, CVSS assessment, or enough information to determine whether the
reported kernel bug represents a practically relevant security issue.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin. It combines
an autonomous classifier with LLM-assisted technical analysis and a
separate ActionableScore mechanism.

The purpose of this report is to prioritize Linux kernel CVEs before
manual review, identify cases that require prompt investigation, and
support automatic closure of issues that are unlikely to have meaningful
security impact.

Published priority for this report: MODERATE REGULAR
Manual review required: NO

A detailed explanation of the methodology and priority rules is included
at the end of this message.

======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================

CVE-2026-98072	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-98072 CHECK WITH IMPACT FROM ORIG NN MODERATE	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H';CWE-362;*CWE-833;CWE-667;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.3';DESCR 'A race in RDS release_in_xmit can lose a wakeup because clear_bit_unlock only provides release ordering and does not order the following wait queue check with a full memory barrier. The releasing CPU can observe an empty wait queue while a waiter still observes RDS_IN_XMIT as set. This can leave rds_conn_shutdown or rds_tcp_reset_callbacks blocked indefinitely in an uninterruptible wait_event with no timeout. The stalled shutdown worker can block further work on its single threaded workqueue and cause an RDS availability failure. For the CVSS the PR:N value in the paranoid score reflects a network adjacent RDS peer that may induce connection failure or teardown without a local account on the target. Reliable triggering still depends on a narrow concurrency window, so AC:H is appropriate. Impact is denial of service only because the affected path provides no UAF, out of bounds access, information leak, or write primitive.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 0)  SKIP CVE-2026-98072 UNKNOWN SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	INIT HARDWARE LINUS TEST 	-	-	checked

======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================

ActionableScore=0
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES

1. ActionableScore

* Raw conservative score: 0
* Conservative score: 0
* Raw paranoid score: 0
* Paranoid score: 0
* No floor or cap was applied.
* Final recommended bucket: **Ordinary Moderate**::

2. Signal breakdown

* +1 Reliable strong DoS. The lost wakeup can leave `rds_conn_shutdown()` or `rds_tcp_reset_callbacks()` blocked indefinitely and strand the single-threaded shutdown worker.
* -1 Hard timing requirement. Triggering requires the specific store-buffering interleaving where the releasing CPU observes an empty wait queue while the waiter still observes `RDS_IN_XMIT` as set. The commit also states that finding waiters is rare.
* No remote-reachability points. A remote RDS peer may influence connection failure, but the supplied evidence does not establish that network traffic alone controls the complete vulnerable interleaving without prior local RDS setup.
* No local-unprivileged points. The complete socket setup, connection state, shutdown, and concurrent transmit sequence is not shown to be available to an ordinary user.
* No memory-corruption points. This is a synchronization failure and lost wakeup, not a UAF, OOB access, stale-object mutation, or overwrite.
* No additional Availability point. The blocked worker is the same DoS consequence already counted.
* No C or I points. There is no disclosure, unauthorized modification, or security-boundary bypass.
* No paranoid escalation. Stronger impact would require an unsupported corruption or broader host-wide failure primitive.

3. Reachability analysis

The vulnerable state requires an RDS transmit release to race with an uninterruptible shutdown or reset waiter. A network-adjacent peer may help cause connection failure or teardown, but the patch does not prove that such a peer can independently create the required local transmit and waiter concurrency.

The privilege needed for the complete trigger is unresolved, so `HostAdminRequired=UNKNOWN`. No capability check or complete namespace-local setup path is supplied, so `NamespaceScopedPrivilege=UNKNOWN`. Prior local RDS socket and connection setup is required, but whether this setup needs a privileged actor is not established. No special hardware is required by the changed generic RDS send path.

The timing dependency is concrete and narrow. Both CPUs must observe stale state in the relevant memory-ordering window before any later sender clears the condition by issuing another wakeup.

4. Primitive and severity interpretation

The exact primitive is a lost wakeup caused by a missing full memory barrier between clearing `RDS_IN_XMIT` and checking the wait queue. The consequence is an indefinitely sleeping shutdown or reset worker and an RDS availability failure.

There is no freed object, stale post-lifetime reference, repeated release, refcount mutation, or active structured-object corruption. This is therefore `CLASS_C`, not Class B or Class A.

The demonstrated consequence is subsystem DoS. Host-wide kernel panic, memory corruption, privilege escalation, disclosure, and integrity compromise are not established. `ImportantCandidate=NO` because no Important-grade primitive remains unresolved. `AutoDowngradeAllowed=YES` because the established behavior is a constrained synchronization DoS without corruption or boundary bypass.

5. One-sentence report phrase

A missing full memory barrier in RDS transmit release can lose a waiter wakeup and leave connection shutdown processing blocked indefinitely, causing an RDS denial of service.

6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Confirm whether an unprivileged local RDS user or a network-adjacent peer can reliably create the complete transmit and teardown sequence, and whether the affected single-threaded workqueue is shared broadly enough to cause impact beyond one connection.

7. Call-site confidence

Call-site confidence: high

======================================================================
UPSTREAM PATCH SUMMARY
======================================================================

Patch: net/rds: use wq_has_sleeper() in release_in_xmit() [ Upstream
Commit: ed7ee0cd0e136d02f87f13181b1a89880463c7e9
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ed7ee0cd0e136d02f87f13181b1a89880463c7e9

Changed files:
  net/rds/ib_recv.c
  net/rds/send.c

Diff excerpt:

Not included in this email. See the upstream URL for the full patch.

Full patch:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ed7ee0cd0e136d02f87f13181b1a89880463c7e9

======================================================================
DETAILED REPORT METHODOLOGY
======================================================================

The original Linux kernel CVE announcement for CVE-2026-98072 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98072

The original CVE announcement normally does not include a security-level
estimate. In particular, it may not contain a CVSS assessment, an impact
level, or enough information to determine whether the reported bug is a
practically relevant security issue. One purpose of this parallel CVE list
is to provide that missing technical and prioritization information.

The original goal of the AL-KERNEL project was to prioritize Linux kernel
CVE analysis automatically before manual review. The system can also help
identify non-security issues that may be suitable for automatic closure.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin.

The first analysis stage combines an autonomous classifier with additional
LLM-based analysis. The autonomous classifier runs locally on a CPU and is
based on a backpropagation neural network. Together, these mechanisms
produce a technical vulnerability description, identify likely weakness
types, estimate CVSS severity, and provide input for ActionableScore.

Two CVSS estimates are retained because incomplete kernel vulnerability
information often permits more than one defensible interpretation:

  Conservative CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
  The Best / paranoid CVSS vector: AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 5.3

The conservative vector represents a lower-impact interpretation.
The Best/paranoid vector intentionally represents a plausible upper-bound
interpretation and should not automatically be treated as demonstrated
real-world impact.

CVSS may also need to be adjusted for a particular Linux deployment,
because actual reachability, privileges, enabled kernel configuration,
hardware, namespaces, exposed device nodes, and other environmental
conditions can differ significantly between systems.

A separate ActionableScore mechanism evaluates practical remediation
urgency. Its analysis may include reachability, attack prerequisites,
subsystem exposure, memory-corruption characteristics, denial-of-service
reliability, and possible confidentiality, integrity, or
privilege-escalation impact.

  Conservative ActionableScore: unknown
  Paranoid ActionableScore: 0

The final base severity is taken directly from the second tab-separated
field of the AL-KERNEL classification result. ActionableScore does not
replace or independently override that final AL-KERNEL decision, and
if ActionableScore adjusted impact level of ALKERNEL, then you would see
self-readable flags above like INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN7.

For an AL-KERNEL result of MODERATE, this report uses the following
additional presentation split:

  ActionableScore below 5   -> MODERATE REGULAR
  ActionableScore 5 or more -> MODERATE 7.0

The distinction between MODERATE REGULAR and MODERATE 7.0 makes it
possible to identify Moderate issues that should receive manual analysis
and fixes before lower-priority MODERATE REGULAR issues. In many cases,
MODERATE REGULAR fixes may wait for a later rebase or routine update.

There is one override in which MODERATE REGULAR becomes MODERATE 7.0
even when the ActionableScore is below 5. When the AL-KERNEL result
contains the KPANIC flag, a MODERATE result is always presented as
MODERATE 7.0. The KPANIC flag selected with few regexps without
usage of AI at all, so it helps to detect cases when Kernel Crash happens
and similar (to filter False-Negative results from the LLM usage).

KPANIC indicates that a reliable kernel crash, kernel panic, or similarly
serious kernel availability impact was identified by the classification
workflow.

AL-KERNEL base severity for this report: MODERATE
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): MODERATE REGULAR

These results are intended to support engineering triage. They are
machine-generated estimates, and cases marked for manual review should
be validated by a human security engineer before final disposition.
For more info read docs linked from here: https://kernelcve.org/
(and you can submit you own patch there to generate such a report
for non-existant CVE-id yet).

Note that in many cases this AI tool selects higher severity, than
real is (means you can expect Importants instead of Moderate 7.0 or
Moderates 7.0 instead of regular Moderates). If you see such cases,
please use reply email interface to add additional manual analyses
info to this particular CVE.
And please, please, let me know when you see Lows instead of Importants
or Important instead of Low (because particular for such cases I
need to tune this AI tool to make it better for this one and next similar).
My contact email for such notifications is alexanjelausa@gmail.com (and both
send reply to CVE record itself too and see "reply" button below for howto reply).