* [CVE-2026-98345][LOW] wifi: cfg80211: check IP header size in cfg80211_classify8021d() [ Upstream
@ 2026-10-10 13:48 21% AL-KERNEL
0 siblings, 0 replies; 1+ results
From: AL-KERNEL @ 2026-10-10 13:48 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-98345
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: wifi: cfg80211: check IP header size in cfg80211_classify8021d() [ Upstream
Commit: 18d5547327c202cda33ad2bbd203220c2c62c8a7
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=18d5547327c202cda33ad2bbd203220c2c62c8a7
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98345
Analysis date: Sat, 10 Oct 2026 09:48:33 -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-2026-98345 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98345
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-2026-98345 LOW https://www.kernelcve.org/list/?q=CVE-2026-98345 CHECK WITH IMPACT FROM ORIG NN LOW | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=0 LEGACY=LOW RESULT=DIFF TEMP_DISTANCE_MERGE_SKIP=AEGIS_NO_POSITIVE_SEVERITY_EVIDENCE (independent Legacy and Aegis differ; FINAL: LOW, Aegis: MODERATE_KPANIC) Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L';*CWE-457;*CWE-20;CWE-126;Other CVSS 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.4';DESCR 'cfg80211_classify8021d can read an uninitialized value when a locally transmitted frame claims to contain IPv4 or IPv6 but is shorter than the corresponding IP header. The invalid value is consumed as a DSCP field during 802.1d queue classification and can produce a KMSAN report or limited availability impact on diagnostic systems configured to panic on warnings. For the CVSS the PR:L value is used because reliable construction and transmission of the malformed frame through AF_PACKET normally requires a local process with CAP_NET_RAW or an equivalent delegated capability. The issue is not directly reachable through ordinary incoming wireless traffic because the demonstrated path originates from local packet_sendmsg transmission. The source path provides no UAF or write primitive and the sampled value is used internally for queue selection, so privilege escalation and a direct information leak are not supported.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 0) MAYBE REMOTE READ KASAN SKB IPV6 SYZBOT PACKET DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 KPANIC_UNSUPPORTED_REMOVED - - checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=0
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=NO
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES
RequiresHostUID0=NO
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=NONE
B4PendingReview=NO
B4PendingConfirmed=NO
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 Weak invalid-read concern. A truncated IPv4 or IPv6 frame causes an uninitialized byte to be consumed as the DSCP value during queue classification.
* -1 Reduced or delegated privilege. The demonstrated AF_PACKET transmission path requires CAP_NET_RAW, but this capability is narrower than host-administrator authority.
* +0 WARN or KMSAN report. The evidence shows an uninitialized-value report, not a production kernel crash.
* +0 Integrity impact. Incorrect DSCP-derived queue selection is an ordinary classification error and does not establish modification of protected state.
* +0 Confidentiality impact. The uninitialized byte is consumed internally and no path returns it to userspace, the network, or another observable output.
* +0 Remote reachability. The demonstrated call chain starts at local packet_sendmsg rather than incoming wireless traffic.
* B5-R is not established because there is no heap OOB write, retry-accumulated offset, or later consumption of corrupted written state.
* B3-PENDING is not established because there is no write to shared or file-backed storage.
* B4-PENDING is not established because no authorization decision or mandatory security guard is involved.
* Controlled corruption, UAF, arbitrary write, disclosure, privilege escalation, and a practical non-crash exploit chain are not demonstrated.
3. Reachability analysis
The demonstrated attacker is a local process transmitting a malformed short frame through AF_PACKET and a mac80211 interface. Creating the relevant packet socket normally requires CAP_NET_RAW in the user namespace governing the network namespace, so numeric host UID 0 and full host-administrator authority are not required.
The complete trigger is not proven to be available inside an attacker-created namespace because access to a suitable wireless interface may depend on host configuration or device assignment. NamespaceScopedPrivilege therefore remains UNKNOWN. A configured mac80211 wireless interface is required, but no unusual hardware or timing race is involved. The operation is deterministic once the attacker has the required packet-socket and interface access.
4. Primitive and severity interpretation
The exact primitive is a limited read of uninitialized bytes outside the valid IPv4 or IPv6 header data in an skb. The resulting value is masked and used as DSCP input for 802.1d transmit-queue classification.
This is CLASS_C invalid-state behavior. It is not a UAF, active-object lifetime violation, overwrite, shared-backing modification, or authorization bypass. The demonstrated consequence is a KMSAN diagnostic and potentially incorrect traffic classification. A fatal result would depend on a diagnostic kernel configuration such as panic_on_warn and is not established for ordinary production kernels.
No useful primitive remains after excluding the diagnostic report. ImportantCandidate is therefore NO, and automatic downgrade is allowed.
5. One-sentence report phrase
A local CAP_NET_RAW process can submit a truncated frame that causes cfg80211 to read an uninitialized DSCP value, but the value only affects internal queue classification and no write, disclosure, UAF, or privilege-escalation primitive is established.
6. Manual review recommendation
NO MANUAL CHECK NEEDED
The patch establishes a constrained internal invalid read with no observable disclosure, memory write, lifetime violation, authorization bypass, or credible Important-grade consequence.
7. Call-site confidence
Call-site confidence: high
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: wifi: cfg80211: check IP header size in cfg80211_classify8021d() [ Upstream
Commit: 18d5547327c202cda33ad2bbd203220c2c62c8a7
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=18d5547327c202cda33ad2bbd203220c2c62c8a7
Changed files:
net/wireless/util.c
net/mac80211/wme.c
net/mac80211/tx.c
net/packet/af_packet.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=18d5547327c202cda33ad2bbd203220c2c62c8a7
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-98345 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98345
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:L/PR:L/UI:N/S:U/C:N/I:N/A:L
The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L
The Best / paranoid CVSS score: 4.4
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).
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