* [CVE-2026-93231][LOW] lockd: fix swapped arguments in nlmsvc_match_ip() [ Upstream
@ 2026-09-24 17:29 21% AL-KERNEL
0 siblings, 0 replies; 1+ results
From: AL-KERNEL @ 2026-09-24 17:29 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-93231
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: lockd: fix swapped arguments in nlmsvc_match_ip() [ Upstream
Commit: 0d72e78c9d38d5377a059a4837f82b65b91cdcf6
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=0d72e78c9d38d5377a059a4837f82b65b91cdcf6
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93231
Analysis date: Thu, 24 Sep 2026 13:29:30 -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-2026-93231 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93231
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: LOW
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-2026-93231 LOW https://www.kernelcve.org/list/?q=CVE-2026-93231 CHECK WITH IMPACT FROM ORIG NN MODERATE Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L';CWE-843;CWE-704;CWE-125;BEST CVSS score: '2.3';DESCR 'A type confusion in the lockd unlock by IP callback causes a server sockaddr to be interpreted as an nlm_host object. The invalid interpretation makes nlm_srcaddr read data at an incorrect offset and normally prevents locks associated with the requested server IP address from being released. For the CVSS the PR:H because writing to proc fs nfsd unlock_ip normally requires administrative control of the NFS server configuration. The issue is not directly network reachable and is triggered through a local NFS server control interface. Impact is limited to failed lock cleanup and possible local availability degradation. The patch context does not demonstrate an information disclosure primitive, memory write, or plausible privilege escalation path.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 0) YES OOB DISK LINUS DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 NO NO checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=0
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=YES
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES
1. ActionableScore
* Raw conservative score: -1
* Conservative score: 0
* Raw paranoid score: -1
* Paranoid score: 0
* Score normalization: negative raw scores are normalized to 0.
* Final recommended bucket: **Ordinary Moderate**::
2. Signal breakdown
* +1 Weak invalid structured-object interpretation. The callback passes a server sockaddr where nlmsvc_match_ip incorrectly treats the argument as struct nlm_host and nlm_srcaddr reads at the nlm_host h_srcaddr offset. This is a limited invalid read and type-confusion-like interpretation, not a demonstrated write or lifetime violation.
* -2 Host-admin-equivalent control is required. The vulnerable operation is initiated by writing to /proc/fs/nfsd/unlock_ip, an NFS server control interface normally restricted to host administrators.
* No remote-reachability points. Network traffic does not directly invoke the vulnerable callback. A local control-plane write initiates lock cleanup.
* No reliable kernel-crash point. The supplied evidence identifies failed address matching and failure to release locks, not an observed kernel Oops, panic, or stable host-wide DoS.
* No confidentiality point. The incorrect read is used for an internal address comparison. No data is returned to userspace, transmitted, or otherwise disclosed.
* No integrity point. The patch does not establish an attacker-controlled write, refcount modification, object replacement, or unauthorized state change.
* No UAF or lifetime signal. No object is freed, released, retired, or subsequently accessed after its lifetime ends.
* No strong semantic reinterpretation signal. The sockaddr versus nlm_host mismatch is concrete, but the consumed value is only used by rpc_cmp_addr for matching and does not represent active attacker-controlled operations, pointers, ownership records, or security-sensitive descriptors.
* No availability point beyond limited cleanup failure. Locks may remain unreleased for the selected server IP, but the evidence does not establish persistent host-wide resource exhaustion or a reliable system crash.
* No paranoid increment. A stronger result would require an unsupported disclosure, fault, write, or corruption consequence.
3. Reachability analysis
The triggering operation is nlmsvc_unlock_all_by_ip through the /proc/fs/nfsd/unlock_ip NFS server control interface. The relevant attacker is a local host administrator or equivalent NFS server management principal, not a remote NLM client.
The complete vulnerable operation is not namespace-scoped. It operates on host NFS server lockd state and requires access to the host NFS server procfs control interface. There is no evidence that an ordinary local user, container user, or namespace-local CAP_NET_ADMIN holder can perform the complete operation.
No special hardware, race condition, device prerequisite, or prior attacker-controlled network setup is relevant. NFS server and lockd activity must exist for the functional cleanup defect to matter, but this is not scored as an additional niche-subsystem penalty because the host-admin restriction already materially limits reachability.
4. Primitive and severity interpretation
The exact defect is a callback argument-order mismatch. nlm_traverse_locks invokes the callback as match(lockhost, host), where lockhost is the actual struct nlm_host and host is the caller-supplied server sockaddr. nlmsvc_match_ip reverses these meanings and passes the sockaddr to nlm_srcaddr as though it were an nlm_host.
This is not an active structured-object UAF, fixed stale storage access, refcount bug, double release, or cleanup lifetime mutation. The incorrect object interpretation results in reading garbage at the expected nlm_host address-field offset and comparing it against an nlm_host incorrectly treated as a sockaddr. The demonstrated outcome is that the comparison practically never matches and locks associated with the requested IP are not released.
PrimitiveClass is CLASS_C because the established behavior is invalid-state and limited invalid-read behavior without an independently useful corruption primitive. No controlled reclaim, arbitrary write, kernel disclosure, callback influence, authorization bypass, privilege escalation, or meaningful cross-boundary effect is established.
ImportantCandidate is NO because the patch-supported impact is failed administrative lock cleanup. AutoDowngradeAllowed is YES because no unresolved concrete memory-corruption, lifetime, ownership, authorization, or security-boundary primitive remains.
5. One-sentence report phrase
A swapped callback argument order in lockd unlock by IP handling causes a sockaddr to be interpreted as an nlm_host, preventing the requested NFS lock cleanup operation from matching and releasing the intended locks.
6. Manual review recommendation
NO MANUAL CHECK NEEDED
The patch establishes an administrative control-plane logic defect with a limited invalid read used only for address comparison. No UAF, write primitive, disclosure path, crash, remote trigger, or privilege-escalation mechanism is supported.
7. Call-site confidence
Call-site confidence: high
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: lockd: fix swapped arguments in nlmsvc_match_ip() [ Upstream
Commit: 0d72e78c9d38d5377a059a4837f82b65b91cdcf6
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=0d72e78c9d38d5377a059a4837f82b65b91cdcf6
Changed files:
fs/lockd/svcsubs.c
include/linux/lockd/lockd.h
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=0d72e78c9d38d5377a059a4837f82b65b91cdcf6
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-93231 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93231
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: Not available
The Best / paranoid CVSS vector: AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L
The Best / paranoid CVSS score: 2.3
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: LOW
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): LOW
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).
^ permalink raw reply [relevance 21%]
Results 1-1 of 1 | reverse | sort options + mbox downloads above
-- links below jump to the message on this page --
2026-09-24 17:29 21% [CVE-2026-93231][LOW] lockd: fix swapped arguments in nlmsvc_match_ip() [ Upstream AL-KERNEL
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox