[CVE-2026-45979][LOW] drm/amdgpu: clean up the amdgpu_cs_parser_bos [ Upstream

[CVE-2026-45979][LOW] drm/amdgpu: clean up the amdgpu_cs_parser_bos [ Upstream

[AL-KERNEL]

CVE: CVE-2026-45979
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: drm/amdgpu: clean up the amdgpu_cs_parser_bos [ Upstream
Commit: 0905a1d4a5500ecf11f1c0079098e3a351d22163
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=0905a1d4a5500ecf11f1c0079098e3a351d22163
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-45979
Analysis date: Sat, 01 Aug 2026 11:35:19 -0400
ActionableScore: 2
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-2026-45979 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-45979

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-2026-45979	LOW	CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';CWE-667;CWE-703;CWE-755;BEST CVSS score: '4.7';DESCR 'amdgpu_cs_parser_bos could return directly on amdgpu_hmm_range_alloc() failure in a low memory condition, bypassing the common cleanup path that is expected to release resources and unlock the mutex. A local user with access to the AMDGPU DRM device can potentially trigger this through command submission under memory pressure, causing later GPU operations to block or hang. For the CVSS the PR:L is used because the attacker needs local execution and access to the DRM device, but no administrative capability is normally required on systems where render nodes are exposed to users. The issue is not network reachable and does not provide a demonstrated memory corruption primitive. Impact is denial of service against the GPU driver path and possibly affected workloads, with no supported confidentiality or integrity impact.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2) 	MAYBE	INIT NOMEMCHK SIMPLEFIX LEAK HARDWARE 	-	-	checked

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

ActionableScore=2

1. ActionableScore
* Conservative score: 2
* Paranoid score: 2
* Final recommended bucket: **Ordinary Moderate / Low-like**::

2. Signal breakdown
* Local unprivileged trigger: +1. A local user with access to the AMDGPU DRM device or render node may reach the command submission path.
* Availability impact realistic: +1. The direct return on allocation failure can bypass cleanup and leave a mutex locked, causing later GPU operations to block or hang.
* No generic memory corruption: +0. The patch shows an error-path cleanup bug, not UAF, double free, OOB write, type confusion, or attacker-controlled overwrite.
* No privilege escalation plausible: +0. There is no demonstrated reclaim, stale object reuse, callback control, arbitrary write, or security boundary bypass.
* No confidentiality or integrity impact: +0. The bug is consistent with local DoS only.
* No high-control GPU API bonus: +0. Although this is a GPU ioctl path, the patch does not show attacker control over memory layout, object lifetime, DMA mappings, refcounts, or page ownership.

3. Reachability analysis
A local process that can submit AMDGPU command streams can potentially trigger the path, especially under low-memory conditions where `amdgpu_hmm_range_alloc()` fails. This usually does not require full administrator privileges if render nodes are exposed to users, but it does require local device access. Containers only matter if the AMDGPU device node is passed through. The path is not network reachable. Realistic exploitation depends on memory pressure and the affected AMDGPU driver path being available.

4. Severity interpretation
This behaves like an ordinary Moderate or Low-like local DoS, not an Important-class vulnerability. The realistic impact is a GPU driver hang or blocked subsequent GPU operations due to skipped cleanup and missing mutex unlock. Theoretical memory corruption is not supported by the patch or commit context.

5. One-sentence report phrase
A local AMDGPU user can trigger an allocation-failure error path in `amdgpu_cs_parser_bos()` that bypasses common cleanup and may leave a mutex locked, causing a local GPU driver denial of service.

6. Manual review recommendation
NO MANUAL CHECK NEEDED. This can be auto-closed for urgent security triage because the issue is local, low-memory dependent, DoS-only, and lacks evidence of memory corruption, privilege escalation, or network reachability.

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

Patch: drm/amdgpu: clean up the amdgpu_cs_parser_bos [ Upstream
Commit: 0905a1d4a5500ecf11f1c0079098e3a351d22163
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=0905a1d4a5500ecf11f1c0079098e3a351d22163

Changed files:
  drivers/gpu/drm/amd/amdgpu/amdgpu_cs.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=0905a1d4a5500ecf11f1c0079098e3a351d22163

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

The original Linux kernel CVE announcement for CVE-2026-45979 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-45979

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:L/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 4.7

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: 2

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).