[CVE-2026-72273][LOW] fbdev: efifb: fix memory leak in efifb_probe() [ Upstream

[CVE-2026-72273][LOW] fbdev: efifb: fix memory leak in efifb_probe() [ Upstream

[AL-KERNEL]

CVE: CVE-2026-72273
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: fbdev: efifb: fix memory leak in efifb_probe() [ Upstream
Commit: fafb2e08741b20027cee77918816de29a32d6fd6
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fafb2e08741b20027cee77918816de29a32d6fd6
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72273
Analysis date: Sat, 15 Aug 2026 09:23:30 -0400
ActionableScore: 0
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2026-72273 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72273

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-2026-72273	LOW	CHECK WITH IMPACT FROM ORIG NN MODERATE	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-401;*CWE-772;CWE-404;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:N';BEST CVSS score: '1.9';DESCR 'efifb_probe leaked the option string returned by fb_get_options because ownership was transferred to the caller but the efifb path did not free it after setup. This is a small memory leak in the framebuffer probe path, not a memory corruption bug, and there is no evident UAF, OOB access, information leak, or privilege escalation primitive. For the CVSS the PR:H is used because reliable triggering normally requires administrative control over boot video options or privileged driver reprobe behavior. The issue is not network reachable and practical impact is negligible to low availability impact only.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 0)	YES	LEAK UAF LINUS  DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_GUESSCVSS	YES	NO	checked

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

ActionableScore=0

1. ActionableScore
* Conservative score: 0
* Paranoid score: 0
* Final recommended bucket: **Ordinary Moderate / Low-like**::

2. Signal breakdown
* No remote reachability: efifb_probe is not network-triggerable.
* No local unprivileged trigger: reliable triggering normally requires boot option control or privileged driver reprobe behavior.
* No memory corruption signal: the patch only adds kfree(option) for an ownership-transfer leak. No UAF, OOB, double-free, type confusion, stale callback, or write primitive is indicated.
* No reliable strong DoS: this appears to be a small probe-path leak, not a realistic fast resource-exhaustion primitive.
* Requires admin/root-like control in typical deployments: -2, but the final score is floored at 0.
* Call-site confidence: high, because the affected allocation use and missing free are visible in the provided probe path.

3. Reachability analysis
The bug is reachable during efifb platform framebuffer probing after fb_get_options returns an option string. Ordinary users cannot normally trigger repeated efifb_probe execution or control early video boot options. Containers and namespaces do not materially lower the privilege requirement because framebuffer platform device probing and boot option handling are host-level operations. The path may exist on EFI framebuffer systems, but the vulnerable condition is a small cleanup omission during probe, not a broadly exposed runtime interface.

4. Severity interpretation
This behaves like a Low or ordinary Moderate cleanup issue, not an actionable Moderate or Important-class kernel vulnerability. The realistic impact is negligible to very low availability impact from a small memory leak. There is no supported theoretical memory corruption primitive and no evidence of privilege escalation, confidentiality impact, integrity impact, or remotely reachable attack surface.

5. One-sentence report phrase
efifb_probe failed to free the option string returned by fb_get_options after setup, causing a small privileged probe-path memory leak without evidence of memory corruption, privilege escalation, or network reachability.

6. Manual review recommendation
NO MANUAL CHECK NEEDED.
This can be auto-closed for triage purposes because it is a small privileged memory leak with no realistic security boundary bypass, no strong DoS, and no memory corruption primitive.

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

Patch: fbdev: efifb: fix memory leak in efifb_probe() [ Upstream
Commit: fafb2e08741b20027cee77918816de29a32d6fd6
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fafb2e08741b20027cee77918816de29a32d6fd6

Changed files:
  drivers/video/fbdev/efifb.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=fafb2e08741b20027cee77918816de29a32d6fd6

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

The original Linux kernel CVE announcement for CVE-2026-72273 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72273

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:H/PR:H/UI:N/S:U/C:N/I:N/A:N
  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: 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 alexanjelausa@gmail.com (and both
send reply to CVE record itself too and see "reply" button below for howto reply).