From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-53141][MODERATE REGULAR] drm/v3d: Fix global performance monitor reference counting Date: Mon, 29 Jun 2026 12:53:53 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-53141 X-AL-KERNEL-Priority: MODERATE REGULAR X-AL-KERNEL-Severity: MODERATE REGULAR X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 3 X-AL-KERNEL-ActionableScore-Lower: 2 X-AL-KERNEL-Commit: 3e1947573140a57119294f0bff39ee18d93f23e1 List-Id: CVE: CVE-2026-53141 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: drm/v3d: Fix global performance monitor reference counting Commit: 3e1947573140a57119294f0bff39ee18d93f23e1 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3e1947573140a57119294f0bff39ee18d93f23e1 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53141 Analysis date: Mon, 29 Jun 2026 12:53:53 -0400 ActionableScore: 3 ActionableScore lower bound: 2 Actionable bucket: Ordinary Moderate / Low-like. Not an Actionable Moderate candidate Manual review required: NO Summary: A local reference-counting bug in the V3D DRM global perfmon ioctl path can leak perfmon objects across SET_GLOBAL, CLEAR_GLOBAL, and delete paths, potentially causing local resource-exhaustion DoS without evidence of memory corruption or privilege escalation. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-53141 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53141 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 REGULAR 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-2026-53141 MODERATE CHECK Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H';*CWE-772;*CWE-401;*CWE-664;Other CVSS 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.5';DESCR 'A reference counting bug in the V3D DRM global perfmon ioctl path can leak perfmon references when SET_GLOBAL fails, when CLEAR_GLOBAL is used, or when the current global perfmon is destroyed. A local process with access to the V3D DRM device can repeatedly exercise these perfmon ioctls and keep kernel perfmon objects referenced longer than intended. For the CVSS the PR:L is used because triggering requires local access to the DRM device interface, but not full administrative privileges in typical render node deployments. The issue is not network reachable and does not depend on packet traffic or a remote peer. Impact is local denial of service through resource leakage or failed cleanup of perfmon objects. There is no clear use-after-free, out-of-bounds access, information leak, or arbitrary write primitive in the patch context.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like. Not an Actionable Moderate candidate (with actual score 3) SKIP CVE-2026-53141 SKIP No affected files built, so skip this CVE NO - - unknown MAYBE INIT LEAK ERRORPATH HARDWARE LINUS INCREASED_FROM_LOW_BASED_ON_HIGHCVSSSCORE DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5 - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=3 ActionableScoreLower=2 ## 1. ActionableScore * Conservative score: 2 * Paranoid score: 3 * Final recommended bucket: **Ordinary Moderate / Low-like. Not an Actionable Moderate candidate**:: ## 2. Signal breakdown Triggered signals: * Local unprivileged trigger: +1 A local process with access to the V3D DRM device can invoke the perfmon SET_GLOBAL, CLEAR_GLOBAL, and delete paths. In typical DRM render-node deployments this does not necessarily require full administrator privileges. * Real lifetime / reference-counting bug: +1 The bug is a reference leak: v3d_perfmon_find() increments the perfmon reference count, but several paths fail to drop it. This is a real object-lifetime accounting issue, but it retains objects too long rather than freeing them too early. Paranoid-only signal: * Availability impact realistic: +1 If the ioctl paths can be exercised repeatedly, leaked perfmon references may accumulate and cause resource exhaustion or failed cleanup. This is sustained-abuse DoS, not immediate memory corruption. Not triggered: * Remote reachable: +0 This is a local DRM ioctl path, not a network path. * Generic memory corruption: +0 The patch shows reference leaks, not UAF, double free, OOB write, type confusion, arbitrary write, or page-cache corruption. * Privilege escalation plausible: +0 No reclaim, stale callback, attacker-controlled reuse, object replacement, write primitive, or type confusion is shown. * Reliable kernel crash / strong DoS: +0 conservatively The commit describes leaked references, not a direct panic, Oops, or immediate system-wide crash. ## 3. Reachability analysis The bug is reachable by a local process that can open the affected V3D DRM device and issue the global perfmon ioctl sequence. In many systems, DRM render nodes may be accessible to non-root users in the video or render group, so PR:L is the practical privilege model. Containers or sandboxes only matter if the V3D DRM device is passed through or otherwise exposed. The path is not network reachable and does not involve packet processing, firmware input, or remote peers. Exposure depends on systems with the V3D driver and perfmon ioctl support available to local users. ## 4. Severity interpretation This behaves like an ordinary Moderate / Low-like local resource-leak issue. The theoretical impact is local DoS through accumulated leaked perfmon references, but the patch does not support memory corruption, information disclosure, integrity impact, or privilege escalation. The paranoid score only raises availability concern for sustained repeated abuse. ## 5. One-sentence report phrase A local reference-counting bug in the V3D DRM global perfmon ioctl path can leak perfmon objects across SET_GLOBAL, CLEAR_GLOBAL, and delete paths, potentially causing local resource-exhaustion DoS without evidence of memory corruption or privilege escalation. ## 6. Manual review recommendation NO MANUAL CHECK NEEDED This is a local reference leak without a demonstrated memory-corruption primitive, security-boundary bypass, remote reachability, or plausible LPE path. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: drm/v3d: Fix global performance monitor reference counting Commit: 3e1947573140a57119294f0bff39ee18d93f23e1 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3e1947573140a57119294f0bff39ee18d93f23e1 Commit description: In the SET_GLOBAL ioctl, v3d_perfmon_find() bumps the reference count on the perfmon it returns, but v3d_perfmon_set_global_ioctl() and v3d_perfmon_delete() fail to release that reference on several paths: 1. v3d_perfmon_set_global_ioctl() leaks the reference on its error paths. 2. CLEAR_GLOBAL leaks both the find reference and the reference previously stashed in v3d->global_perfmon by the SET_GLOBAL ioctl that configured it. 3. Destroying a perfmon that is the current global perfmon leaks the reference stashed by the SET_GLOBAL ioctl. Release each of these references explicitly. Cc: stable@vger.kernel.org Fixes: c6eabba ("drm/v3d: Add DRM_IOCTL_V3D_PERFMON_SET_GLOBAL") Reviewed-by: Iago Toral Quiroga Link: https://patch.msgid.link/20260531-v3d-perfmon-lifetime-v2-1-60ed4485a203@igalia.com Signed-off-by: Maíra Canal Signed-off-by: Greg Kroah-Hartman Changed files: drivers/gpu/drm/v3d/v3d_perfmon.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=3e1947573140a57119294f0bff39ee18d93f23e1 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-53141 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53141 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:U/C:N/I:N/A:L The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS score: 5.5 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: 2 Paranoid ActionableScore: 3 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: NO Published priority for this report (same as in Subject): MODERATE REGULAR 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).