[CVE-2026-98842][LOW] module: fix lost error code from codetag_load_module()

[AL-KERNEL <alkernel@kernelcve.org>]

CVE: CVE-2026-98842
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: module: fix lost error code from codetag_load_module()
Commit: 258310d59a82ea4854bfd9138682bbaac1153b19
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=258310d59a82ea4854bfd9138682bbaac1153b19
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98842
Analysis date: Sat, 24 Oct 2026 04:25:36 -0400
ActionableScore: 1
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO

Summary:
A privileged failed module load could incorrectly report success and leak livepatch ELF metadata, without evidence of memory corruption or authorization bypass.

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ABOUT THIS REPORT
======================================================================

The original Linux kernel CVE announcement for CVE-2026-98842 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98842

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.

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AL-KERNEL CLASSIFICATION RESULT
======================================================================

CVE-2026-98842	LOW	https://www.kernelcve.org/list/?q=CVE-2026-98842 CHECK WITH IMPACT FROM ORIG NN LOW | AEGIS IMPACT LOW AEGIS_AS=0 LEGACY=LOW RESULT=SAME (final reconciliation agrees; DECISION: both LOW)	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';CWE-755;*CWE-401;CWE-703;BEST CVSS score: '1.9';DESCR 'A module loading logic error discarded the failure code from codetag_load_module, allowing load_module to return success after the failed module had already been torn down. A livepatch module could additionally leak mod klp_info because its temporary ELF metadata was not freed on this error path. For the CVSS the PR:H value reflects that direct module or livepatch loading normally requires CAP_SYS_MODULE and control of module input. The demonstrated primitives are an incorrect return value and limited resource retention. There is no evidence of UAF, OOB access, arbitrary write, information disclosure, or a partially loaded module remaining active. Automated impact decision path. The original SimpleNet classifier selected LOW. The primary LLM estimated paranoid CVSS 1.9 and the production ActionableScore returned 1 with recommendation Ordinary Moderate. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. No severity changing production threshold or specialist override was recorded. The legacy KP specialist has no review artifact for this run. The legacy FD or DH downgrade specialist has no review artifact for this run. The independent weaker Aegis shadow evaluated CVSS 0.0 and ActionableScore 0 with primitive class CLASS_C and manual review REQUIRED. Its independently reconciled impact was LOW. The shadow agreed with the final production impact and aggregation did not change that impact. The final reported impact is LOW.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1)	MAYBE	SIMPLEFIX LEAK ERRORPATH LINUS 	-	-	checked

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ACTIONABLESCORE ANALYSIS
======================================================================

ActionableScore=1
PrimitiveClass=NONE
RealUAF=NO
HostAdminRequired=YES
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES
RequiresHostUID0=NO
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=NONE
B4PendingReview=NO
B4PendingConfirmed=NO

1. ActionableScore

* Raw base score: 1.
* Conservative score: 1; no floor or cap applied.
* Raw paranoid score: 1.
* Paranoid score: 1; no technically supported additional impact.
* Final recommended bucket: **Ordinary Moderate**::

2. Signal breakdown

* +1 Concrete persistent kernel resource leak: when `codetag_load_module()` fails for a livepatch module, `mod->klp_info` allocated by `copy_module_elf()` is not released. The new `livepatch_cleanup` path calls `free_module_elf(mod)`.
* +0 Incorrect success result: failure from `codetag_load_module()` was discarded, so teardown occurred but `load_module()` could return zero. No active partially loaded module or authorization change is shown.
* No UAF, OOB write, stale-object use, shared-backing write, disclosure, or protected-state corruption is evidenced.
* No crash or material resource-exhaustion impact is established, so no DoS point is awarded.
* B5-R does not apply: there is no retry-accumulated OOB write or later consumption of corrupted structured state.
* B4 does not apply: no mandatory authorization guard changes from DENY to ALLOW.

3. Reachability analysis

The complete operation is kernel module or livepatch loading, normally gated by effective host `CAP_SYS_MODULE`. Numeric host UID 0 is not intrinsically required, but effective host-administrator power is. The operation is global rather than a complete namespace-scoped capability path. No race, unusual hardware, or remote entry exists.

4. Primitive and severity reading

The exact defects are a lost negative error code and a bounded error-path metadata leak. The failed module is torn down; no surviving active module, memory corruption, lifetime violation, or protected-resource access is shown. `PrimitiveClass=NONE`, and automatic downgrade is safe.

5. One-sentence report phrase

A privileged failed module load could incorrectly report success and leak livepatch ELF metadata, without evidence of memory corruption or authorization bypass.

6. Manual review advice

NO MANUAL CHECK NEEDED

The patch establishes only privileged error propagation and cleanup defects.

7. Call-site confidence

Call-site confidence: high

======================================================================
UPSTREAM PATCH SUMMARY
======================================================================

Patch: module: fix lost error code from codetag_load_module()
Commit: 258310d59a82ea4854bfd9138682bbaac1153b19
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=258310d59a82ea4854bfd9138682bbaac1153b19

Commit description:

If codetag_load_module() fails, err is not set to reflect the failure
and load_module() returns 0 after the module has been torn down.

Also, if the module is a livepatch, mod->klp_info allocated by
copy_module_elf() leaks on this error path.  Free it via a new
livepatch_cleanup label.

Link: https://lore.kernel.org/20260827030503.49171-1-hao.ge@linux.dev
Fixes: 044d2ae ("alloc_tag: handle module codetag load errors as module load failures")
Signed-off-by: Hao Ge <hao.ge@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reported-by: Sashiko <sashiko-bot@kernel.org>
Suggested-by: Petr Pavlu <petr.pavlu@suse.com>
Reviewed-by: Bradley Morgan <brads@mainlining.org>
Cc: Aaron Tomlin <atomlin@atomlin.com>
Cc: Luis Chamberalin <mcgrof@kernel.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  kernel/module/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=258310d59a82ea4854bfd9138682bbaac1153b19

======================================================================
DETAILED REPORT METHODOLOGY
======================================================================

The original Linux kernel CVE announcement for CVE-2026-98842 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98842

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:H/PR:H/UI:N/S:U/C:N/I:N/A:L
  The Best / paranoid CVSS score: 1.9

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 alexanjelausa@gmail.com (and both
send reply to CVE record itself too and see "reply" button below for howto reply).