* [CVE-2026-80932][MODERATE REGULAR] vsock/virtio: flush works in dependency order
@ 2026-09-11 22:03 21% AL-KERNEL
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From: AL-KERNEL @ 2026-09-11 22:03 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-80932
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: vsock/virtio: flush works in dependency order
Commit: 2187a56f2fd1715d54daed6392809223c60544f3
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2187a56f2fd1715d54daed6392809223c60544f3
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80932
Analysis date: Fri, 11 Sep 2026 18:03:26 -0400
ActionableScore: 3
ActionableScore lower bound: 2
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-2026-80932 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80932
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: YES
A detailed explanation of the methodology and priority rules is included
at the end of this message.
======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================
CVE-2026-80932 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-80932 CHECK WITH IMPACT FROM ORIG NN MODERATE Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H';*CWE-416;CWE-362;CWE-667;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7';DESCR 'A use-after-free can occur in the virtio VSOCK remove path because work items are flushed in an order that does not match their producer and consumer dependencies. tx_work can queue send_pkt_work, and send_pkt_work can later queue rx_work after rx_work was already flushed by virtio_vsock_remove(). This allows rx_work to run after kfree(vsock), and KASAN reports slab-use-after-free in virtio_transport_rx_work. For the CVSS the PR:L is used for paranoid scoring because a local actor with VSOCK access may be able to shape pending work while device removal or delegated device control happens in the same guest or service context. The issue is not directly network reachable over IP and is mainly relevant to virtualized environments using virtio VSOCK. Impact is at least denial of service via kernel crash. In worst case it may allow confidentiality or integrity impact because the bug is a real UAF race rather than a simple warning or resource leak.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline / manual review recommended (with actual score 3) YES READ DANGER VIRT INIT RACE UAF INCREASED_TO_MODERATE7_BASED_ON_GUESSCVSS DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 NO NO checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=3
ActionableScoreLower=2
PrimitiveClass=CLASS_B
RealUAF=YES
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
1. ActionableScore
* Raw conservative score: 2
* Conservative score: 2. No floor or cap applied.
* Raw paranoid score: 3
* Paranoid score: 3. No floor or cap applied.
* Final recommended bucket: **Borderline / manual review recommended**::
2. Signal breakdown
Conservative signals:
* +2 Real UAF / lifetime violation. KASAN reports slab-use-after-free in virtio_transport_rx_work after virtio_vsock_remove frees the enclosing virtio_vsock object.
* +1 Reliable kernel crash / strong DoS. The demonstrated stale workqueue execution can dereference freed kernel memory and crash the kernel.
* -1 Hard or narrow timing / teardown ordering. The issue depends on an async remove-path ordering where rx_work is flushed before send_pkt_work can queue it again.
Paranoid signals:
* +2 Real UAF / lifetime violation. Same as conservative.
* +1 Reliable kernel crash / strong DoS. Same as conservative.
* 0 Race penalty withheld. The producer-to-consumer dependency is concrete, and pending work can make the ordering issue reproducible in testing.
Important non-awarded signals:
* Controlled reclaim not demonstrated.
* Arbitrary or directed kernel write not demonstrated.
* Confidentiality and integrity impact not awarded. The evidence shows stale read / dereference and crash, not disclosure or attacker-controlled modification.
* Remote network reachability not established. VSOCK is involved, but the vulnerable operation is device remove cleanup, not normal IP packet processing.
* Local unprivileged trigger not awarded. A local user may use VSOCK, but the complete trigger also needs virtio_vsock_remove or equivalent device removal.
* Structured stale-object leverage not awarded. The stale object is a driver context used by rx_work, but attacker-controlled replacement or meaningful post-reuse field consumption is not established.
* Concrete repeated release/refcount not awarded. There is no visible second put/release/refcount mutation on the same dangling reference.
* Weak LPE not awarded merely because this is a UAF.
* Extra Availability not awarded because the same crash is already counted once.
Repeated release/refcount check:
* First release can end lifetime: yes, kfree(vsock) frees the object.
* Exact same reference survives: rx_work can still reference the freed enclosing object.
* Second operation is a real lifetime/refcount mutation: no, the demonstrated stale operation is a dereference in rx_work, not a second release/refcount mutation.
* +1 Concrete repeated release/refcount awarded: no.
* Paranoid repeated-refcount leverage awarded: no.
* FLOOR 5 applied: no.
3. Reachability analysis
The demonstrated stale use occurs in the virtio VSOCK device remove path. The producer chain is tx_work to send_pkt_work to rx_work, and the old flush order allowed rx_work to be queued after it had already been flushed.
A normal local user may be able to create VSOCK activity and influence whether work exists, but the supplied evidence does not establish that an ordinary user can trigger the complete device removal sequence. virtio_vsock_remove is normally reached through driver removal, device hot unplug, module unload, or virtualization device lifecycle actions. Those operations are usually controlled by guest administrator, host administrator, or the virtualization stack, but the supplied input does not fully resolve the exact attacker boundary.
Namespace scoped privilege is not established. No evidence shows that all required stages can be completed inside attacker-created namespaces.
Prior host or administrator setup may exist because the system must have virtio VSOCK configured. This is common in virtualized environments but not necessarily active on all systems. No rare physical hardware requirement is indicated.
Race repeatability is moderate to uncertain. The bad ordering is concrete, but exploitation depends on workqueue timing during teardown.
4. Primitive and severity interpretation
The exact primitive is an async post-teardown use-after-free. virtio_vsock_remove frees the virtio_vsock object while rx_work can still be queued and later executed.
This is closer to fixed driver-context stale storage than to a strong active-object exploitation primitive. The stale object is structured, but the demonstrated use is an async workqueue dereference after device removal, with KASAN showing a crash. There is no evidence of controlled reclaim, controlled replacement object contents, callback hijack, arbitrary read/write, or a second lifetime/refcount mutation.
PrimitiveClass is CLASS_B because a real kernel lifetime violation is established. It is not CLASS_A because no strong exploitation primitive is demonstrated. It is not CLASS_C because the issue is a real UAF, not only an invalid state or warning.
Demonstrated consequence is kernel crash / DoS. Speculative consequence is broader memory-corruption exploitation, but the supplied evidence does not establish enough leverage to preserve Important severity automatically.
ImportantCandidate is NO because this appears constrained to cleanup/remove-path async stale use with crash-only evidence and no meaningful unresolved reuse or repeated lifetime mutation. ManualReview is RECOMMENDED because it is still a KASAN-confirmed kernel UAF in a virtualization transport path. AutoDowngradeAllowed is YES because the currently established primitive is constrained and does not show controlled corruption, boundary bypass, or repeated refcount/lifetime mutation.
Likely operational severity is borderline Moderate. It should not be treated as a strong Important candidate without additional evidence showing below-admin triggerability or exploitation leverage beyond crash.
5. One-sentence report phrase
A virtio VSOCK remove-path ordering bug can let rx_work run after kfree(vsock), causing a KASAN-confirmed use-after-free and likely kernel crash, but current evidence does not establish controlled reclaim, privilege escalation, or direct remote reachability.
6. Manual review recommendation
MANUAL CHECK RECOMMENDED
Reason: this is a real KASAN-confirmed UAF, but the visible path is a constrained device-remove/workqueue ordering issue with crash-only evidence and unresolved attacker reachability.
7. Call-site confidence
Call-site confidence: high
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: vsock/virtio: flush works in dependency order
Commit: 2187a56f2fd1715d54daed6392809223c60544f3
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2187a56f2fd1715d54daed6392809223c60544f3
Commit description:
virtio_vsock_remove() stops the virtqueues and then flushes each work
item before freeing the enclosing virtio_vsock. The current order does
not account for dependencies between those items: tx_work may queue
send_pkt_work, and send_pkt_work may queue rx_work.
In particular, send_pkt_work can set restart_rx and release tx_lock.
The remove path can then stop the queues and flush rx_work before
send_pkt_work queues it. Although the later send_pkt_work flush waits
for that producer to finish, nothing waits for the newly queued rx_work,
so kfree(vsock) can race with it.
KASAN reported:
BUG: KASAN: slab-use-after-free in
virtio_transport_rx_work+0x487/0x4b0
Read of size 8 at addr ffff888114c2b008 by task kworker/1:1/47
Workqueue: virtio_vsock virtio_transport_rx_work
Call Trace:
virtio_transport_rx_work+0x487/0x4b0
process_one_work+0x688/0x1120
worker_thread+0x45b/0xd10
Allocated by task 1:
virtio_vsock_probe+0xef/0x6b0
Freed by task 84:
kfree+0x131/0x3c0
virtio_vsock_remove+0xd1/0x100
Flush the works in producer-to-consumer order. virtio_vsock_vqs_del()
has already disabled the queue callbacks and cleared the run flags, so
after tx_work and send_pkt_work are drained, no source remains that can
queue rx_work after its flush.
Fixes: 0ea9e1d ("VSOCK: Introduce virtio_transport.ko")
Cc: [email protected]
Signed-off-by: Chengfeng Ye <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Paolo Abeni <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Changed files:
net/vmw_vsock/virtio_transport.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=2187a56f2fd1715d54daed6392809223c60544f3
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-80932 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80932
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:H/UI:N/S:U/C:N/I:N/A:H
The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
The Best / paranoid CVSS score: 7
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: 2
Paranoid ActionableScore: 3
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 [email protected] (and both
send reply to CVE record itself too and see "reply" button below for howto reply).
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