From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-68252][LOW] drm/amdgpu/sdma7.0: replace BUG_ON() with WARN_ON() Date: Mon, 10 Aug 2026 14:28:00 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-68252 X-AL-KERNEL-Priority: LOW X-AL-KERNEL-Severity: LOW X-AL-KERNEL-Base-Severity: LOW X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 2 X-AL-KERNEL-ActionableScore-Lower: 1 X-AL-KERNEL-Commit: 395bf099ef7153227600a2d8cb087f45c4a277b6 List-Id: CVE: CVE-2026-68252 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: drm/amdgpu/sdma7.0: replace BUG_ON() with WARN_ON() Commit: 395bf099ef7153227600a2d8cb087f45c4a277b6 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=395bf099ef7153227600a2d8cb087f45c4a277b6 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68252 Analysis date: Mon, 10 Aug 2026 14:28:00 -0400 ActionableScore: 2 ActionableScore lower bound: 1 Actionable bucket: Ordinary Moderate / Low-like Manual review required: NO Summary: AMDGPU SDMA 7.0 used `BUG_ON()` for a misaligned fence address check, allowing a local GPU path to panic the kernel if the internal invariant is violated, with no evidence of memory corruption or privilege escalation. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68252 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68252 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-2026-68252 LOW CHECK WITH IMPACT FROM ORIG NN LOW 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-617;CWE-703;CWE-754;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.5';DESCR 'amdgpu SDMA 7.0 used BUG_ON when emitting a fence if the fence address was not aligned to a 4 byte boundary. If this internal invariant was violated, the host kernel could panic instead of only reporting the bad condition. For the CVSS the PR:L is used for the higher score because unprivileged local users may have access to DRM render nodes and can submit GPU workloads, even though the exact misaligned fence address is normally driver controlled. The issue is not network reachable and requires local interaction with the GPU driver path. Impact is denial of service via kernel crash only. No credible memory corruption, information disclosure, or privilege escalation primitive is indicated by this patch.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2) SKIP CVE-2026-68252 UNKNOWN SKIP No affected files built, so skip this CVE NO - - unknown MAYBE WARNONLY SIMPLEFIX HARDWARE INCREASED_FROM_LOW_BASED_ON_HIGHCVSSSCORE DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5 DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=2 ActionableScoreLower=1 ## 1. ActionableScore * Conservative score: **1** * Paranoid score: **2** * Final recommended bucket: **Ordinary Moderate / Low-like** ## 2. Signal breakdown Conservative signals: * Reliable kernel crash / strong DoS: **+1**. The original code used `BUG_ON(addr & 0x3)`, so if the misaligned fence address condition is reached, the kernel can panic. * Hard or unreliable trigger / special condition: **-1**. The fence address appears to be an internal driver value, not clearly attacker-controlled from the patch. * Availability impact realistic: **+1**. A triggered `BUG_ON()` is host-wide availability impact. Conservative total: **1** Paranoid additional signal: * Local unprivileged trigger: **+1**. Local users may have access to DRM render nodes and may be able to exercise GPU submission paths, although direct control over the misaligned fence address is not shown. Paranoid total: **2** Not counted: * No generic memory corruption. The patch only replaces `BUG_ON()` with `WARN_ON()`. * No UAF, OOB write, double free, type confusion, refcount misuse, or arbitrary write primitive is shown. * No confidentiality or integrity impact is supported. * No privilege escalation path is indicated. * No network reachability. ## 3. Reachability analysis The affected path is in the AMDGPU SDMA 7.0 fence emission code. A local user may be able to reach GPU submission paths through DRM render nodes, but the checked `addr` value is normally produced by the kernel driver rather than directly supplied by userspace. This makes reliable triggering uncertain. Namespaces or containers may matter only if GPU device nodes are delegated into the container. Without access to the AMDGPU device node, the bug is not reachable. The path is hardware-dependent and applies only to systems using affected AMDGPU SDMA 7.0 hardware and driver support. Call-site confidence: **medium**. The changed function is visible, but the full caller chain and user control over `addr` are not provided. ## 4. Severity interpretation This behaves like an ordinary local DoS issue, not an Important-class vulnerability. The realistic impact is kernel panic if an internal alignment invariant is violated. The theoretical concern is limited to availability because the patch does not show memory corruption, stale object lifetime, attacker-controlled overwrite, information disclosure, or privilege escalation. ## 5. One-sentence report phrase AMDGPU SDMA 7.0 used `BUG_ON()` for a misaligned fence address check, allowing a local GPU path to panic the kernel if the internal invariant is violated, with no evidence of memory corruption or privilege escalation. ## 6. Manual review recommendation **NO MANUAL CHECK NEEDED** This can be handled as low-priority Moderate or Low-like triage unless additional evidence shows that unprivileged users can reliably force the misaligned fence address or that the warning masks a deeper corruption path. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: drm/amdgpu/sdma7.0: replace BUG_ON() with WARN_ON() Commit: 395bf099ef7153227600a2d8cb087f45c4a277b6 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=395bf099ef7153227600a2d8cb087f45c4a277b6 Commit description: There's no need to crash the kernel for these cases. Reviewed-by: Vitaly Prosyak Signed-off-by: Alex Deucher (cherry picked from commit 9723a8b ) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman Changed files: drivers/gpu/drm/amd/amdgpu/sdma_v7_0.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=395bf099ef7153227600a2d8cb087f45c4a277b6 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68252 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68252 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:N/I:N/A:H 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: 1 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).