From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-68250][LOW] drm/amdgpu/sdma5.2: replace BUG_ON() with WARN_ON() Date: Mon, 10 Aug 2026 11:32:19 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-68250 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: 01dfea84df919cfbec4064151d327480ae5c120d List-Id: CVE: CVE-2026-68250 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: drm/amdgpu/sdma5.2: replace BUG_ON() with WARN_ON() Commit: 01dfea84df919cfbec4064151d327480ae5c120d Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=01dfea84df919cfbec4064151d327480ae5c120d Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68250 Analysis date: Mon, 10 Aug 2026 11:32:19 -0400 ActionableScore: 2 ActionableScore lower bound: 1 Actionable bucket: Ordinary Moderate / Low-like Manual review required: NO Summary: A reachable BUG_ON() in the amdgpu SDMA 5.2 fence emission path could allow a local GPU user to trigger a kernel panic if a misaligned internal fence address reaches the function, but the patch does not indicate memory corruption or privilege escalation. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68250 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68250 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-2026-68250 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-617;CWE-755;CWE-703;BEST CVSS score: '4.7';DESCR 'A reachable BUG_ON() in the amdgpu SDMA 5.2 fence emission path could panic the kernel if a fence address with non zero low alignment bits reaches sdma_v5_2_ring_emit_fence(). This is best classified as a local denial of service caused by an overly fatal assertion rather than memory corruption. For the CVSS the PR:L is used because a local process with access to GPU or DRM execution paths is the most plausible attacker model, while no administrator privileges are clearly required for ordinary render node access. The attack complexity is high because the checked address appears to be an internal driver fence address and is not obviously under direct user control. The issue is not network reachable. Impact is denial of service only via kernel panic, with no supported confidentiality or integrity impact.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2) SKIP CVE-2026-68250 UNKNOWN SKIP No affected files built, so skip this CVE NO - - unknown MAYBE WARNONLY SIMPLEFIX HARDWARE - - 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 * Local unprivileged trigger: +1 A local process with access to AMD GPU DRM or render node paths may plausibly reach SDMA fence emission, although direct control over the checked address is not shown. * Reliable kernel crash / strong DoS: +1 The original code used BUG_ON(addr & 0x3), which can panic the kernel if a misaligned fence address reaches this path. * Hard or unreliable trigger / special condition: -1 The fence address appears to be an internal driver-generated address, not an obviously attacker-controlled userspace value. Reliable triggering is therefore uncertain. * Broad/default/common subsystem: +1 only in paranoid interpretation AMD GPU DRM render nodes are common on affected hardware, but this is still hardware and generation specific, so this is not counted in the conservative score. No memory corruption, UAF, OOB write, type confusion, arbitrary write, page-cache corruption, or privilege-escalation primitive is supported by the patch. ## 3. Reachability analysis The most plausible trigger is local use of GPU or DRM execution paths on systems with affected AMDGPU SDMA 5.2 hardware. Ordinary render node access may be enough to exercise GPU command submission paths, so PR:L is a reasonable CVSS-style assumption. However, the exact BUG_ON condition depends on a misaligned internal fence address, and the patch does not show that userspace can directly choose or reliably corrupt this value. This is not network reachable. Containers or namespaces may matter only if the GPU device node is delegated into the container. The affected path is not universal because it depends on AMDGPU hardware and this SDMA generation. ## 4. Severity interpretation This behaves like an ordinary local DoS issue caused by an overly fatal kernel assertion. The realistic impact is kernel panic if the internal invariant fails. Theoretical impact does not extend to memory corruption or privilege escalation based on the provided patch. The paranoid score remains low because the only concrete primitive is BUG_ON-triggered panic. There is no evidence of attacker-controlled overwrite, stale pointer reuse, object confusion, or sensitive data exposure. ## 5. One-sentence report phrase A reachable BUG_ON() in the amdgpu SDMA 5.2 fence emission path could allow a local GPU user to trigger a kernel panic if a misaligned internal fence address reaches the function, but the patch does not indicate memory corruption or privilege escalation. ## 6. Manual review recommendation NO MANUAL CHECK NEEDED This can be handled as a low-priority local DoS/assertion fix unless your product exposes AMDGPU render nodes to untrusted tenants and has evidence that userspace can reliably force the misaligned fence address. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: drm/amdgpu/sdma5.2: replace BUG_ON() with WARN_ON() Commit: 01dfea84df919cfbec4064151d327480ae5c120d Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=01dfea84df919cfbec4064151d327480ae5c120d 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 ae658af ) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman Changed files: drivers/gpu/drm/amd/amdgpu/sdma_v5_2.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=01dfea84df919cfbec4064151d327480ae5c120d ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68250 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68250 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: 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).