* [CVE-2026-98068][MODERATE 7.0] net/rds: don't let rds_conn_shutdown() consume a concurrent drop [ Upstream
@ 2026-09-25 11:26 21% AL-KERNEL
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From: AL-KERNEL @ 2026-09-25 11:26 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-98068
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: net/rds: don't let rds_conn_shutdown() consume a concurrent drop [ Upstream
Commit: bd1cb197a07111ca8d4f4c21411c56a3c85a9797
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bd1cb197a07111ca8d4f4c21411c56a3c85a9797
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98068
Analysis date: Fri, 25 Sep 2026 07:26:58 -0400
ActionableScore: 4
ActionableScore lower bound: unknown
Actionable bucket: Borderline / manual review recommended
Manual review required: YES
Summary:
No one-sentence report phrase was found.
======================================================================
ABOUT THIS REPORT
======================================================================
The original Linux kernel CVE announcement for CVE-2026-98068 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98068
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 7.0
Manual review required: YES
A detailed explanation of the methodology and priority rules is included
at the end of this message.
======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================
CVE-2026-98068 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-98068 CHECK WITH IMPACT FROM ORIG NN IMPORTANT Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H';CWE-362;*CWE-416;CWE-667;Other CVSS 'AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7.5';DESCR 'A race between rds_conn_shutdown() and a concurrent RDS path drop can cause an in flight shutdown to consume RDS_CONN_ERROR and make the shutdown pass queued by the drop a no-op. A newly accepted socket may then remain installed with active callbacks while the path is already marked RDS_CONN_DOWN, causing an unbounded receive queue, a wedged peer send path, and denial of service. During network namespace teardown or module unload, a pending destroy can suppress the successor shutdown pass while reconnect delayed work remains armed. The path may then be freed before that work executes, creating a plausible use-after-free condition with potential confidentiality, integrity, and availability impact. A remote RDS peer can contribute to the race by sending a FIN, but successful triggering also depends on concurrent teardown, reset, or path replacement activity. For the CVSS the PR:N value is used for the paranoid score because the remote peer does not need privileges on the target once it can communicate with the RDS endpoint. AV:A reflects the common deployment of RDS inside a trusted cluster or data center network. AC:H reflects the required race window and concurrent state transition. Impact is at least denial of service and the delayed work after path free scenario may permit broader memory corruption effects.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline / manual review recommended (with actual score 4) SKIP CVE-2026-98068 UNKNOWN SKIP No affected files built, so skip this CVE NO - - unknown MAYBE INIT RACE ERRORPATH IMPROVEONLY TIMER LINUS KPANIC INCREASED_TO_MODERATE7_BASED_ON_GUESSCVSS - - checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=4
PrimitiveClass=CLASS_B
RealUAF=YES
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
1. ActionableScore
* Raw conservative score: 3
* Conservative score: 4
* Raw paranoid score: 3
* Paranoid score: 4
* Applied conservative REAL UAF FLOOR 4: 3 -> 4.
* Applied paranoid REAL UAF FLOOR 4: 3 -> 4.
* Final recommended bucket: **Borderline / manual review recommended**::
2. Signal breakdown
* +2 Real UAF or lifetime violation. During pending destruction, `rds_conn_path_destroy()` can free `struct rds_conn_path` while its embedded reconnect delayed work remains armed and can execute afterward.
* +1 Concrete persistent resource or reference leak. In the separate non-destroy race, a newly installed socket can remain established with callbacks armed and membership in `rds_tcp_tc_list`, while its path remains stuck in `RDS_CONN_DOWN`.
* +1 Realistic kernel crash. Execution of reconnect work after its containing path has been freed can produce a host kernel fault.
* -1 Hard one-shot race. The UAF path requires a FIN or drop to intersect pending path destruction while shutdown work is being flushed. The report states that reproduction used widened race windows.
* Controlled reclaim, attacker-shaped replacement contents, arbitrary read or write, and callback-pointer control are not demonstrated.
* No structured stale-object leverage point was awarded. The delayed work represents active stale use, but attacker control over reclaim or post-free fields is not established.
* No additional availability point was awarded for the same possible kernel crash.
* No confidentiality or integrity points were awarded from the paranoid CVSS alone.
* No concrete repeated release or refcount operation exists. The first operation is path destruction, but the later operation is delayed-work execution rather than a second put, free, or refcount mutation on the same reference.
* The dedicated repeated-release point and paranoid repeated-refcount point were therefore withheld.
* FLOOR 5 was not applied because complete below-host-admin reachability and meaningful reuse leverage are not established.
3. Reachability analysis
An RDS peer can contribute to the race by causing a TCP FIN and the accept path can install a replacement socket. This does not establish direct remote exploitation of the complete UAF sequence because the post-free delayed-work case additionally requires concurrent path destruction, such as network-namespace teardown or module unload.
Module unload is host-admin controlled. Network-namespace teardown might be induced below host administrator in some configurations, but the supplied evidence does not establish that the complete RDS setup, connection lifecycle, destroy operation, and race are available in attacker-created namespaces. Consequently, both host-admin and namespace-scoped privilege requirements remain unknown.
The RDS endpoint and connection must already exist. The input does not establish whether an attacker can independently instantiate the complete topology or whether privileged prior setup is mandatory. No special hardware is required. The race appears narrow and partially dependent on another actor or lifecycle event rather than being fully controlled by the remote peer.
4. Primitive and severity interpretation
The exact primitive is an asynchronous use-after-free candidate involving an embedded reconnect delayed-work object whose owner, `struct rds_conn_path`, may be freed while the work remains armed. This is active structured storage rather than a fixed transfer buffer, but the supplied patch does not show attacker-controlled reclaim, replacement contents, arbitrary memory access, or exploitation of reclaimed callback state.
The ordinary path produces a persistent socket and queue leak that wedges the RDS connection. The destruction path is stronger because delayed work may execute after the containing path is freed. This is CLASS_B lifetime corruption, not merely CLASS_C invalid state, but it is also not CLASS_A because no controlled exploitation primitive is established.
The demonstrated consequences are a wedged path, an accumulating receive queue, and plausible kernel crash. Broader confidentiality, integrity, or privilege-escalation effects remain speculative. ImportantCandidate is NO because the currently supported UAF is a narrow teardown race without meaningful demonstrated reuse leverage. AutoDowngradeAllowed is YES because this is presently a constrained crash-oriented Class B case, although manual validation remains advisable due to the armed-work-after-free condition.
Likely operational severity is Moderate, with greater concern on RDS deployments where peers can repeatedly induce FIN and connection replacement activity during namespace or module teardown.
5. One-sentence report phrase
A race in RDS shutdown can leave a socket permanently attached or allow reconnect work to execute after its connection path is freed, causing connection wedging, resource growth, or a kernel crash.
6. Manual review recommendation
MANUAL CHECK RECOMMENDED
Confirm whether an unprivileged or remote actor can induce the complete destroy race and whether `cp_conn_w` can execute after allocator reuse in a way that consumes attacker-influenced state.
7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: net/rds: don't let rds_conn_shutdown() consume a concurrent drop [ Upstream
Commit: bd1cb197a07111ca8d4f4c21411c56a3c85a9797
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bd1cb197a07111ca8d4f4c21411c56a3c85a9797
Changed files:
net/rds/connection.c
net/rds/tcp.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=bd1cb197a07111ca8d4f4c21411c56a3c85a9797
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-98068 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98068
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:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
The Best / paranoid CVSS vector: AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
The Best / paranoid CVSS score: 7.5
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: 4
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: YES
Published priority for this report (same as in Subject): MODERATE 7.0
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 [email protected] (and both
send reply to CVE record itself too and see "reply" button below for howto reply).
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