* [CVE-2026-98074][LOW] bonding: do not clear curr_active_slave prematurely when releasing all slaves [ Upstream
@ 2026-09-25 16:05 21% AL-KERNEL
0 siblings, 0 replies; 1+ results
From: AL-KERNEL @ 2026-09-25 16:05 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-98074
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: bonding: do not clear curr_active_slave prematurely when releasing all slaves [ Upstream
Commit: d6ef22e79c2be3612868daede0e9a84f05439d9e
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d6ef22e79c2be3612868daede0e9a84f05439d9e
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98074
Analysis date: Fri, 25 Sep 2026 12:05:07 -0400
ActionableScore: 1
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-2026-98074 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98074
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-2026-98074 LOW https://www.kernelcve.org/list/?q=CVE-2026-98074 CHECK WITH IMPACT FROM ORIG NN LOW Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N';*CWE-772;CWE-284;*CWE-200;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N';BEST CVSS score: '3.3';DESCR 'A bonding teardown bug can leave a former active physical interface in promiscuous mode when a backup slave is released before the active slave. The condition occurs during local bond configuration teardown and may weaken expected network traffic isolation by allowing the interface to receive frames addressed to other MAC addresses. For the CVSS the PR:L in the paranoid score reflects environments where network administration is delegated to a container root or service account with CAP_NET_ADMIN. The issue is not directly network reachable. Practical traffic capture generally also requires local packet capture privileges such as CAP_NET_RAW. Impact is limited potential confidentiality exposure. NO MANUAL CHECK REQUIRED COULD BE AUTOCLOSED.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1) YES INIT LEAK NETWORK HARDWARE LINUS DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 NO NO checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=1
PrimitiveClass=NONE
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES
1. ActionableScore
* Raw conservative score: 1
* Conservative score: 1
* Raw paranoid score: 1
* Paranoid score: 1
* Final recommended bucket: **Ordinary Moderate**::
2. Signal breakdown
* +1 Concrete persistent kernel resource or reference leak. The physical netdevice promiscuity reference count is incremented through rlb_teach_disabled_mac_on_primary and is not decremented during the affected bond teardown ordering. This leaves promiscuous mode enabled after the bond is destroyed.
* No UAF or lifetime corruption signal. curr_active_slave is cleared prematurely, but the patch establishes a logic and cleanup ordering error rather than use of freed storage.
* No controlled write, arbitrary write, object replacement, stale pointer dereference, refcount mutation through freed memory, or callback control is demonstrated.
* No confidentiality point awarded. Promiscuous mode permits the interface to accept additional Ethernet frames, but the supplied evidence does not establish that an attacker can read those frames without separate packet capture privileges. An actor with sufficient CAP_NET_RAW or equivalent packet capture authority can generally request promiscuous reception independently.
* No integrity point awarded. The bug does not modify protected data, credentials, policy, packet contents, or another principals configuration beyond leaving a local interface mode enabled.
* No reliable kernel crash or availability point awarded. The demonstrated result is a leaked promiscuity state, not an Oops, panic, deadlock, or host wide resource exhaustion.
* No remote reachability point awarded. The vulnerable transition is bond configuration teardown and is not triggered by ordinary incoming packet traffic.
* No local unprivileged trigger point awarded. The supplied patch does not establish that an ordinary unprivileged user can create the necessary bond topology, attach the relevant slaves, and execute the complete teardown sequence.
* No privilege penalty applied. Host administrator equivalent privilege is not positively established from the supplied context. The relevant operations likely involve CAP_NET_ADMIN, but the precise target network namespace and whether host owned physical interfaces are required are not fully resolved.
* No niche subsystem penalty applied. Bonding is configuration dependent, but no negative score is applied merely because it is not active by default.
3. Reachability analysis
The trigger requires a bond using the ALB path, an active slave and a backup slave, and bond destruction in the ordering where the backup slave is released before the active slave. The actor must be able to create, configure, and destroy the relevant bonding configuration and manage the involved network devices.
Bond configuration operations are normally guarded by network administration permissions. However, the supplied patch does not show the exact netlink capability checks, the user namespace governing those checks, or whether the physical slave interfaces must be host owned. Therefore HostAdminRequired is UNKNOWN rather than YES or NO.
NamespaceScopedPrivilege is also UNKNOWN. Bond devices can be namespace aware, but the patch does not establish that an attacker can perform the complete operation against the relevant slave devices using only attacker obtainable namespace scoped privileges. The presence of a network namespace or container alone would not prove this.
There is no network packet based trigger. A remote party sending traffic to the interface cannot by itself cause the bond teardown sequence. There is no hardware prerequisite beyond ordinary Ethernet interfaces capable of participating in a bond. This is an ordered cleanup logic issue, not a timing race.
4. Primitive and severity interpretation
The exact primitive is a persistent network interface state cleanup failure. During bond destruction, curr_active_slave is cleared before the active slave transition handling runs. This prevents bond_alb_handle_active_change from decrementing the promiscuity counter that was previously incremented for the active physical interface.
This is neither active structured stale storage nor fixed stale storage. It is not a UAF, double release, refcount operation through freed storage, out of bounds access, or memory corruption bug. There is no concrete repeated release or refcount mutation on a dangling object.
The demonstrated consequence is that the former active physical interface can remain in promiscuous mode after bond teardown. The plausible security consequence is limited weakening of expected local Ethernet traffic filtering. A separate local packet capture capability would normally still be needed to obtain useful traffic. No protected resource theft, authorization bypass, privilege escalation, information disclosure path, or integrity modification is established.
PrimitiveClass is NONE because no meaningful corruption, lifetime, authorization, or ownership primitive is established. ImportantCandidate is NO because the issue is a configuration state leak with no demonstrated exploitation leverage beyond the leaked promiscuous state. AutoDowngradeAllowed is YES because no unresolved memory corruption, security boundary bypass, or meaningful post lifetime primitive exists.
Likely operational severity is Low. Administrators should still apply the fix where bonding with ALB is used, particularly on systems where physical interface promiscuous state is monitored or relied upon for network segmentation policy.
5. One-sentence report phrase
A bonding teardown ordering bug can leave a former active slave interface in promiscuous mode after bond destruction, but no memory corruption, remote trigger, privilege escalation, or direct packet disclosure path is established.
6. Manual review recommendation
NO MANUAL CHECK NEEDED
The patch establishes a bounded local cleanup defect that leaks promiscuous interface state. It does not establish a UAF, kernel corruption, authorization bypass, direct remote trigger, or a concrete confidentiality or integrity primitive.
7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: bonding: do not clear curr_active_slave prematurely when releasing all slaves [ Upstream
Commit: d6ef22e79c2be3612868daede0e9a84f05439d9e
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d6ef22e79c2be3612868daede0e9a84f05439d9e
Changed files:
drivers/net/bonding/bond_main.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=d6ef22e79c2be3612868daede0e9a84f05439d9e
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-98074 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98074
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:H/UI:N/S:U/C:L/I:N/A:N
The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
The Best / paranoid CVSS score: 3.3
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: 1
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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