From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-53329][IMPORTANT] drm/amd/display: Use krealloc_array() in dal_vector_reserve() Date: Wed, 01 Jul 2026 10:12:29 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-53329 X-AL-KERNEL-Priority: IMPORTANT X-AL-KERNEL-Severity: IMPORTANT X-AL-KERNEL-Base-Severity: IMPORTANT X-AL-KERNEL-KPANIC: YES X-AL-KERNEL-ActionableScore: 7 X-AL-KERNEL-ActionableScore-Lower: 5 X-AL-KERNEL-Commit: 31180638a33acad12c863132704a76536fb66211 List-Id: CVE: CVE-2026-53329 Priority: IMPORTANT AL-KERNEL base severity: IMPORTANT KPANIC flag: YES Patch: drm/amd/display: Use krealloc_array() in dal_vector_reserve() Commit: 31180638a33acad12c863132704a76536fb66211 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=31180638a33acad12c863132704a76536fb66211 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53329 Analysis date: Wed, 01 Jul 2026 10:12:29 -0400 ActionableScore: 7 ActionableScore lower bound: 5 Actionable bucket: Strong Important candidate / Actionable Moderate at minimum Manual review required: YES Summary: An integer overflow in `drm/amd/display` `dal_vector_reserve()` can cause an undersized allocation and subsequent kernel heap overflow during vector appends, making this a local memory-corruption issue with DoS impact and plausible LPE risk. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-53329 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53329 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: IMPORTANT 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-2026-53329 IMPORTANT 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:H/I:H/A:H';CWE-190;CWE-131;CWE-122;*CWE-787;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H';BEST CVSS score: '7';DESCR 'An integer overflow in drm/amd/display dal_vector_reserve can make capacity multiplied by struct_size wrap to a smaller allocation size. Subsequent vector appends may then write past the end of the reallocated heap buffer, creating a kernel heap overflow condition. For the CVSS the PR:L is used because reliable triggering is expected to require local access to DRM display control paths or an equivalent local process context, not remote network access. The issue is not network reachable in the normal model and depends on AMD display driver exposure and controllable display or modeset state. Impact is at least local denial of service via memory corruption and in the paranoid case may allow confidentiality or integrity impact including privilege escalation, so it should be reviewed manually.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Strong Important candidate / Actionable Moderate at minimum (with actual score 7) SKIP CVE-2026-53329 SKIP No affected files built, so skip this CVE NO - - unknown MAYBE SIMPLEFIX HARDWARE KPANIC INCREASED_TO_MODERATE_FROM_LOW_BASED_ON_GUESSCVSS KPANIC INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN7 - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=7 ActionableScoreLower=5 ## 1. ActionableScore * Conservative score: 5 * Paranoid score: 7 * Final recommended bucket: **Strong Important candidate / Actionable Moderate at minimum**:: ## 2. Signal breakdown Conservative signals: * Local unprivileged trigger: +1. Likely reachable by a local process with access to DRM display control paths, for example via `/dev/dri/card*` permissions, seat access, or equivalent local graphics stack context. * Memory corruption, strong corruption primitive: +2. The commit explicitly states that `capacity * vector->struct_size` can wrap and cause an undersized `krealloc()`, followed by heap overflows on later vector appends. * Weak LPE concern: +1. Kernel heap overflow makes privilege escalation plausible, but the patch does not show attacker-controlled target selection, reclaim, object replacement, or a demonstrated write primitive. * Reliable kernel crash / strong DoS: +1. A kernel heap overflow in the AMD display driver can realistically crash or destabilize the kernel. * Broad/default/common subsystem on affected hardware: +1. AMDGPU display code is commonly enabled and loaded by default on systems with affected AMD graphics hardware. * Hard or configuration-dependent triggering: -1. Reaching a wrapping `capacity` likely requires a specific display/vector growth path and high-control modeset or display-state conditions. Paranoid additions: * Privilege escalation plausible: upgraded from weak +1 to strong +2 in the paranoid score because the patch explicitly describes a kernel heap overflow, a bug class that historically warrants manual LPE review. * Integrity impact plausible: +1. In the paranoid interpretation, an out-of-bounds heap write may corrupt adjacent kernel objects even though no concrete exploit primitive is shown. Not counted: * No remote reachable signal. This is not a network protocol or packet-processing path. * No firmware-mediated external influence signal based on the provided patch. * No Dirty-Pipe-like or page-cache corruption signal. * No confidentiality impact in the conservative score because no information leak or read-back primitive is described. ## 3. Reachability analysis The realistic trigger is local, through AMD DRM display functionality. The likely attacker model is a local user or process that can access DRM display control interfaces, not a remote network attacker. Namespaces and containers may matter if DRM device nodes are passed through to a container or if a graphical/session service exposes modeset control on behalf of a user. In ordinary deployments, `/dev/dri/card*` access is often limited to local seat users, the `video` group, display managers, or privileged graphics services, so PR:L is more appropriate than PR:N. The affected path is hardware-dependent but not rare on AMD GPU systems. The main uncertainty is call-site controllability: the patch shows the vulnerable allocator helper and the commit states that later vector appends can overflow, but the exact external input path that drives `capacity` to a wrapping value is not included. Call-site confidence: medium. ## 4. Severity interpretation This should not be treated as an ordinary Moderate auto-close candidate. The conservative interpretation is Actionable Moderate because the patch directly fixes an integer-overflow-to-heap-overflow condition in kernel space. The paranoid interpretation is a Strong Important candidate because kernel heap overflow can plausibly become LPE if the vector contents, append pattern, or neighboring heap layout are attacker-influenceable. Theoretical memory corruption potential is strong and explicitly supported by the commit. Realistic exploitation evidence is incomplete because no concrete reclaim, target object corruption, or working LPE path is shown. ## 5. One-sentence report phrase An integer overflow in `drm/amd/display` `dal_vector_reserve()` can cause an undersized allocation and subsequent kernel heap overflow during vector appends, making this a local memory-corruption issue with DoS impact and plausible LPE risk. ## 6. Manual review recommendation MANUAL CHECK REQUIRED The patch explicitly describes a kernel heap overflow, and even though triggerability and exploit control are not fully demonstrated, this bug class should be manually reviewed for local privilege escalation potential. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: drm/amd/display: Use krealloc_array() in dal_vector_reserve() Commit: 31180638a33acad12c863132704a76536fb66211 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=31180638a33acad12c863132704a76536fb66211 Commit description: [Why & How] dal_vector_reserve() computes the allocation size as "capacity * vector->struct_size" using uint32_t arithmetic, which can silently wrap to a small value on overflow. This would cause krealloc to return a smaller buffer than expected, leading to heap overflows on subsequent vector appends. Replace krealloc() with krealloc_array() which performs an internal overflow check and returns NULL on wrap, preventing the issue. Fixes: 2004f45 ("drm/amd/display: Use kernel alloc/free") Assisted-by: Copilot:claude-opus-4.6 Reviewed-by: Alex Hung Signed-off-by: Harry Wentland Signed-off-by: Ray Wu Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher (cherry picked from commit 3766856 ) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman Changed files: drivers/gpu/drm/amd/display/dc/basics/vector.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=31180638a33acad12c863132704a76536fb66211 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-53329 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53329 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:L/UI:N/S:U/C:L/I:L/A:H The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H The Best / paranoid CVSS score: 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: 5 Paranoid ActionableScore: 7 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: IMPORTANT KPANIC detected for this report: YES Published priority for this report (same as in Subject): IMPORTANT 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).