* [CVE-2026-97957][MODERATE 7.0] net: hinic: fix mailbox segment buffer overflow [ Upstream
@ 2026-09-26 19:03 21% AL-KERNEL
0 siblings, 0 replies; 1+ results
From: AL-KERNEL @ 2026-09-26 19:03 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-97957
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: net: hinic: fix mailbox segment buffer overflow [ Upstream
Commit: eca54a092d5f7b497b458ff5a6f66d4f7bfb6674
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=eca54a092d5f7b497b458ff5a6f66d4f7bfb6674
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97957
Analysis date: Sat, 26 Sep 2026 15:03:57 -0400
ActionableScore: 5
ActionableScore lower bound: 3
Actionable bucket: Actionable Moderate
Manual review required: YES
Summary:
No one-sentence report phrase was found.
======================================================================
ABOUT THIS REPORT
======================================================================
The original Linux kernel CVE announcement for CVE-2026-97957 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97957
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-2026-97957 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-97957 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:L/UI:N/S:C/C:H/I:H/A:H';*CWE-787;CWE-120;CWE-193;Other CVSS 'AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H';BEST CVSS score: '8.8';DESCR 'A heap based out of bounds write exists in the HINIC PF mailbox receive path because the segment length validation allows the final mailbox segment to extend beyond the 2048 byte receive buffer. A segment with seq_id 42 can start at offset 2016 and carry 48 bytes, resulting in a write of up to 16 bytes beyond the end of the buffer. A malicious VF may trigger the condition through PF VF mailbox communication. This is relevant when an untrusted guest or tenant controls an assigned virtual function while the vulnerable PF driver runs on the host. For the CVSS the PR:L value is used because reliable triggering requires control of a VF mailbox endpoint, usually through a guest with access to the assigned device or a local process with device administration capability. The guest to host boundary results in Scope Changed. Impact is at least host kernel memory corruption and denial of service. In the worst case the heap overflow may affect confidentiality and integrity or enable privilege escalation, but exploitability depends on allocator layout and the overwritten adjacent object. YES REQUIRES MANUAL CHECK';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate (with actual score 4) YES REMOTE OOB SIMPLEFIX NETWORK KPANIC KPANIC INCREASED_TO_HIGH_BASED_ON_GUESSCVSS DECREASED_TO_MODERATE7_BASED_ON_FALSEPOSCHECKOFKP YES NO checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=5
ActionableScoreLower=3
PrimitiveClass=CLASS_A
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=YES
ManualReview=REQUIRED
AutoDowngradeAllowed=NO
1. ActionableScore
* Raw conservative score: 3
* Conservative score: 3
* Raw paranoid score: 4
* Paranoid score: 5
* Applied paranoid floor: 4 -> 5 because a concrete attacker-influenced host-kernel out-of-bounds write is established and must not be automatically downgraded before reachability and overwrite-control review.
* Final recommended bucket: **Actionable Moderate**::
2. Signal breakdown
Positive signals:
* +2 Strong corruption primitive. The final mailbox segment can write up to 16 bytes beyond a 2048 byte receive buffer. The segment length and mailbox payload originate from the VF to PF mailbox path. This is a concrete kernel heap out-of-bounds write, not only an invalid-state condition.
* +1 Firmware-mediated external influence. The vulnerable receive handler is named recv_pf_from_vf_mbox_handler and processes PF VF mailbox traffic. The attacker-controlled input is delivered through device mailbox communication rather than an ordinary local syscall.
Paranoid-only interpretation:
* +1 Integrity plausible. The overflow directly modifies kernel heap memory beyond the intended receive buffer. The overwritten adjacent object and practical security relevance are not visible in the supplied context.
* No additional speculative exploitation points were added. The resulting raw paranoid score is 4, but the actionable floor raises it to 5 because the patch establishes a concrete kernel write primitive with unresolved PF VF security-boundary implications.
Important non-awarded signals:
* Controlled reclaim or attacker-selected target object is not demonstrated.
* Arbitrary kernel write is not demonstrated. The overwrite is bounded to at most 16 bytes after a fixed receive buffer.
* Reliable host crash is not demonstrated by the supplied commit. Therefore no separate crash or availability point is awarded.
* Remote network reachability is not established. This is mailbox traffic from a VF, not ordinary Ethernet packet processing.
* Guest-to-host exploitation is not established. The code supports PF VF communication, but the supplied evidence does not prove that an untrusted guest can control a VF on an affected host.
* Local unprivileged trigger is not awarded because the complete chain for obtaining and controlling a VF is not shown.
* No privilege penalty is applied. The evidence does not positively establish that host-admin-equivalent privilege is required.
3. Reachability analysis
The vulnerable operation receives mailbox segments from a VF and processes them in the PF driver. A triggering actor must control a VF mailbox endpoint or otherwise be able to submit malformed mailbox segments through the affected HINIC device.
Possible attacker roles include a guest assigned an SR IOV VF, a tenant with direct VF access, or a local privileged device-management process. The supplied patch does not establish which of these actors can complete the full trigger sequence in a particular deployment.
Host-admin-equivalent access is therefore unresolved. Assigning a VF to a guest normally requires prior host-side setup, but prior setup alone does not prove that the guest must have host-admin privileges to trigger the bug after assignment. Namespace-scoped privilege is also unresolved because the patch contains no relevant capability checks or namespace context.
This is not direct network reachability. An external network peer cannot be assumed to invoke the PF VF mailbox path merely by sending Ethernet traffic. Hardware and driver support for the HINIC PF VF mailbox path is required. No race is involved.
4. Primitive and severity interpretation
The exact primitive is an out-of-bounds heap write of up to 16 bytes. With seq_id equal to 42, the receive offset is 2016. The previous validation allowed seg_len equal to 48, causing writes through byte 2063 while MBOX_MAX_BUF_SZ is 2048.
This is not a UAF and does not involve repeated release or refcount mutation. It is not a crash-only invalid dereference. The VF controls the mailbox segment that reaches the fixed PF receive buffer, but the supplied patch does not show the adjacent heap object, payload-copy details, heap layout control, object replacement, callback use, arbitrary read or write, or a demonstrated privilege-escalation chain.
The issue is classified as CLASS_A because an attacker-influenced out-of-bounds write into host kernel memory is directly established. The write is nevertheless materially constrained because its target is adjacent to a fixed mailbox buffer and its maximum overrun is only 16 bytes.
ImportantCandidate is YES because this is a concrete memory-corruption primitive in a PF VF boundary path. Manual review is required to determine whether affected deployments expose VFs to untrusted guests or tenants and whether the 16-byte overwrite can affect security-relevant adjacent objects. AutoDowngradeAllowed is NO because automatic closure would discard a demonstrated kernel heap corruption primitive before the attacker and deployment boundary are resolved.
Likely operational severity is Actionable Moderate pending deployment review. It can become a Strong Important candidate if untrusted guest-controlled VFs are confirmed and the overwrite can corrupt meaningful host kernel state.
5. One-sentence report phrase
A malformed final PF VF mailbox segment can write up to 16 bytes beyond a fixed HINIC kernel receive buffer, creating a constrained host-kernel heap overflow that requires manual review of VF reachability and adjacent-object corruption impact.
6. Manual review recommendation
MANUAL CHECK REQUIRED
A concrete bounded kernel heap out-of-bounds write is established in a PF VF mailbox path, while the practical attacker role, VF assignment model, payload control, and adjacent heap-object impact remain unresolved.
7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: net: hinic: fix mailbox segment buffer overflow [ Upstream
Commit: eca54a092d5f7b497b458ff5a6f66d4f7bfb6674
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=eca54a092d5f7b497b458ff5a6f66d4f7bfb6674
Changed files:
drivers/net/ethernet/huawei/hinic/hinic_hw_mbox.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=eca54a092d5f7b497b458ff5a6f66d4f7bfb6674
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-97957 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97957
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:C/C:L/I:L/A:H
The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
The Best / paranoid CVSS score: 8.8
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: 3
Paranoid ActionableScore: 5
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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