From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-68430][LOW] drm/amdgpu/gfx8: drop unecessary BUG_ON() Date: Tue, 11 Aug 2026 21:06:10 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-68430 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: 0 X-AL-KERNEL-Commit: ab05af6c345bc8460052c60de657ce6d4a2386f7 List-Id: CVE: CVE-2026-68430 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: drm/amdgpu/gfx8: drop unecessary BUG_ON() Commit: ab05af6c345bc8460052c60de657ce6d4a2386f7 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ab05af6c345bc8460052c60de657ce6d4a2386f7 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68430 Analysis date: Tue, 11 Aug 2026 21:06:10 -0400 ActionableScore: 2 ActionableScore lower bound: 0 Actionable bucket: Ordinary Moderate / Low-like Manual review required: NO Summary: A reachable BUG_ON in the AMDGPU gfx8 KIQ fence path may allow a local GPU user to crash the kernel if the internal 64bit fence flag case is reached, but the patch shows no memory corruption or privilege escalation primitive. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68430 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68430 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-2026-68430 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 'A reachable BUG_ON in the AMDGPU gfx8 KIQ fence emission path could panic the kernel if AMDGPU_FENCE_FLAG_64BIT is passed to gfx_v8_0_ring_emit_fence_kiq. The visible primitive is an assertion based crash rather than memory corruption, with no evidence of UAF, OOB access, information disclosure, or arbitrary write. For the CVSS the PR:L is used for the paranoid interpretation because local users may have access to GPU device nodes and may be able to exercise GPU driver paths, although reliable control of this internal flag is not clear from the patch. The issue is not network reachable and the expected impact is denial of service via kernel crash only.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 1) SKIP CVE-2026-68430 UNKNOWN SKIP No affected files built, so skip this CVE NO - - unknown MAYBE OOB DANGER KERNEL_PANIC_PLUS_UAF HARDWARE PACKET DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=2 ActionableScoreLower=0 ## 1. ActionableScore * Conservative score: 0 * Paranoid score: 2 * Final recommended bucket: **Ordinary Moderate / Low-like**:: ## 2. Signal breakdown Conservative signals: * Reliable kernel crash / strong DoS: +1. The patch removes a reachable BUG_ON(), and the commit says there is no need to crash the kernel for this case. * Hard or unreliable trigger / unclear call-path control: -1. The patch does not show that an unprivileged user can directly control AMDGPU_FENCE_FLAG_64BIT in gfx_v8_0_ring_emit_fence_kiq(). * Hardware / driver specific condition: -1. The issue is limited to AMDGPU gfx8 KIQ fence emission, not a broad kernel path. Conservative result is clamped to 0. Paranoid signals: * Local unprivileged trigger: +1. Local users may have access to AMD GPU render nodes and can exercise GPU driver paths. * Reliable kernel crash / strong DoS: +1. If this internal flag case is reachable, BUG_ON() causes an immediate kernel panic. * No memory corruption signal. The patch only removes an assertion and does not show UAF, OOB access, double free, type confusion, arbitrary write, or information disclosure. Paranoid result: 2. ## 3. Reachability analysis The bug is local and device dependent. It requires an AMDGPU gfx8 environment and reaching the KIQ fence emission path with AMDGPU_FENCE_FLAG_64BIT set. Ordinary users may be able to access GPU device nodes on many desktop or compute systems, but the patch does not prove reliable user control over this specific internal flag. It is not network reachable. Containers only matter if GPU device nodes are passed through into the container. ## 4. Severity interpretation This behaves like an ordinary Moderate or Low-like DoS issue rather than an Important-class vulnerability. The visible primitive is assertion-based kernel crash only. There is no evidence of memory corruption, privilege escalation, confidentiality impact, integrity impact, callback control, object lifetime abuse, or shared-page corruption. ## 5. One-sentence report phrase A reachable BUG_ON in the AMDGPU gfx8 KIQ fence path may allow a local GPU user to crash the kernel if the internal 64bit fence flag case is reached, but the patch shows no memory corruption or privilege escalation primitive. ## 6. Manual review recommendation NO MANUAL CHECK NEEDED This can be auto-closed or handled as low-priority Moderate unless a downstream advisory or reproducer shows that unprivileged users can reliably trigger the flag path at scale. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: drm/amdgpu/gfx8: drop unecessary BUG_ON() Commit: ab05af6c345bc8460052c60de657ce6d4a2386f7 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ab05af6c345bc8460052c60de657ce6d4a2386f7 Commit description: There's no need to crash the kernel for this case. Reviewed-by: Vitaly Prosyak Signed-off-by: Alex Deucher (cherry picked from commit 4d7c252 ) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman Changed files: drivers/gpu/drm/amd/amdgpu/gfx_v8_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=ab05af6c345bc8460052c60de657ce6d4a2386f7 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68430 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68430 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: 0 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).