From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-97425][MODERATE 7.0] drm/amdgpu: fix buffer overflow during vBIOS update [ Upstream Date: Thu, 24 Sep 2026 17:24:14 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-97425 X-AL-KERNEL-Priority: MODERATE 7.0 X-AL-KERNEL-Severity: MODERATE 7.0 X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: YES X-AL-KERNEL-ActionableScore: 5 X-AL-KERNEL-ActionableScore-Lower: unknown X-AL-KERNEL-Commit: c7b2af01ee2ecfb8f2289dc83524d8fb1ec72992 List-Id: CVE: CVE-2026-97425 Priority: MODERATE 7.0 AL-KERNEL base severity: MODERATE KPANIC flag: YES Patch: drm/amdgpu: fix buffer overflow during vBIOS update [ Upstream Commit: c7b2af01ee2ecfb8f2289dc83524d8fb1ec72992 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c7b2af01ee2ecfb8f2289dc83524d8fb1ec72992 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97425 Analysis date: Thu, 24 Sep 2026 17:24:14 -0400 ActionableScore: 5 ActionableScore lower bound: unknown Actionable bucket: Actionable Moderate / Strong Important candidate requiring manual review Manual review required: YES Summary: No one-sentence report phrase was found. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-97425 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97425 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 7.0 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-2026-97425 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-97425 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:H/I:H/A:H';*CWE-787;*CWE-20;CWE-1284;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:H/A:H';BEST CVSS score: '7.8';DESCR 'The psp_vbflash sysfs binary attribute had no declared maximum size, so the VFS layer did not restrict the write position to AMD_VBIOS_FILE_MAX_SIZE_B. A local actor with write access to this attribute could submit a vBIOS update at an out-of-bounds position and cause an attacker influenced write beyond the intended buffer. This is a kernel memory corruption primitive that can cause a crash and denial of service. Depending on the adjacent allocation layout and the degree of control provided by amdgpu_psp_vbflash_write, it may also permit privilege escalation or other confidentiality and integrity impact. For the CVSS the PR:L value is used in the paranoid score because access may be delegated through device permissions or a reduced capability service account and does not always require unrestricted root. The issue is not network reachable and requires local access to the amdgpu psp_vbflash interface. Impact is at least a local denial of service via kernel memory corruption and in the worst defensible case may include privilege escalation.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate / Strong Important candidate requiring manual review (with actual score 5) SKIP CVE-2026-97425 UNKNOWN SKIP No affected files built, so skip this CVE NO - - unknown MAYBE OOB HARDWARE KPANIC KPANIC INCREASED_TO_HIGH_BASED_ON_GUESSCVSS DECREASED_TO_MODERATE7_BASED_ON_FALSEPOSCHECKOFKP - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=5 PrimitiveClass=CLASS_A RealUAF=NO HostAdminRequired=UNKNOWN NamespaceScopedPrivilege=NO ImportantCandidate=YES ManualReview=REQUIRED AutoDowngradeAllowed=NO 1. ActionableScore * Raw conservative score: 4 * Conservative score: 5 * Raw paranoid score: 4 * Paranoid score: 5 * Applied conservative safety floor: 4 -> 5 because an attacker-influenced kernel OOB write is established. * Applied paranoid safety floor: 4 -> 5 for the same concrete corruption primitive. No additional speculative exploitation points were added. * Final recommended bucket: **Actionable Moderate / Strong Important candidate requiring manual review**:: 2. Signal breakdown Positive signals: * +2 Strong corruption primitive. The unlimited sysfs binary attribute permits an attacker-influenced write beyond the intended vBIOS update buffer. * +1 Integrity plausible. The operation writes outside the authorized buffer and can modify adjacent kernel memory. * +1 Reliable kernel crash or strong DoS. An OOB kernel write realistically supports an Oops, panic, or other fatal corruption. No double-counting: * Strong LPE leverage was not separately awarded because no controlled adjacent object, directed security-field overwrite, or demonstrated privilege-escalation chain is supplied. * Memory-layout invariant restoration was not separately awarded because it describes the same OOB primitive. * No extra Availability point was awarded for the same possible crash. * Confidentiality was not awarded because no read-back or disclosure path is established. * Local unprivileged reachability was not awarded because mode 0660 alone does not identify the owner, group, or actual delegation policy. * No privilege penalty was applied because host-admin-equivalent access is not positively established. * Remote reachability is not established. * Controlled reclaim, callback influence, credential overwrite, and arbitrary kernel read are not demonstrated. 3. Reachability analysis The trigger requires local write access to the physical GPU sysfs attribute `psp_vbflash`. Its mode is 0660, but the supplied evidence does not identify its runtime owner and group or prove whether a compositor, graphics service, firmware-update service, delegated device-management account, or only host root can write it. Therefore HostAdminRequired is UNKNOWN rather than YES or NO. This is not an ordinary DRM rendering or KMS operation available merely because a user is logged in. No complete path is shown for an ordinary desktop user, DRM master, or compositor to write the vBIOS flashing attribute. The interface is tied to a physical AMD GPU and is not an attacker-created namespace resource. No namespace-scoped capability chain is involved. No race is required. Once write permission is available, the vulnerable condition is an invalid position or size accepted through the sysfs binary attribute. AMDGPU hardware and vBIOS update support are prerequisites, but common AMD GPU hardware is not sufficient evidence for a rare-hardware penalty. 4. Primitive and severity interpretation The exact primitive is an attacker-influenced out-of-bounds kernel write caused by the absence of a maximum size on `psp_vbflash`. Setting `.size` to `AMD_VBIOS_FILE_MAX_SIZE_B` makes the VFS reject positions beyond the intended update buffer. This is not a UAF, stale-object access, repeated release, or cleanup-only fault. It is CLASS_A because a concrete OOB write is directly established. The demonstrated practical consequence is kernel memory corruption with plausible crash and integrity impact. Privilege escalation remains a technically plausible but unproven consequence. The supplied patch does not show the complete `amdgpu_psp_vbflash_write` implementation, allocation layout, attainable offsets, adjacent object types, or whether writes can reach exploitation-relevant fields. Those missing details prevent scoring a demonstrated LPE or arbitrary write, but they do not justify automatically downgrading a concrete kernel overwrite. ImportantCandidate is YES because the primitive can potentially affect adjacent kernel objects and requires exploitation-leverage analysis. AutoDowngradeAllowed is NO because automatic Moderate closure would discard an unresolved controlled-corruption primitive. Operational severity is at least Actionable Moderate, with Important classification dependent on access permissions and the degree of offset and payload control. 5. One-sentence report phrase A writable amdgpu vBIOS sysfs attribute lacked a maximum size and allowed an attacker with access to perform an out-of-bounds kernel write, creating a crash-capable corruption primitive that requires manual analysis for privilege-escalation potential. 6. Manual review recommendation MANUAL CHECK REQUIRED Review the full write callback, buffer allocation, offset arithmetic, maximum reachable position, attacker control over bytes, adjacent allocations, and actual sysfs ownership and group permissions. 7. Call-site confidence Call-site confidence: medium ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: drm/amdgpu: fix buffer overflow during vBIOS update [ Upstream Commit: c7b2af01ee2ecfb8f2289dc83524d8fb1ec72992 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c7b2af01ee2ecfb8f2289dc83524d8fb1ec72992 Changed files: drivers/gpu/drm/amd/amdgpu/amdgpu_psp.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=c7b2af01ee2ecfb8f2289dc83524d8fb1ec72992 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-97425 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97425 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:H/UI:N/S:U/C:L/I:H/A:H The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H The Best / paranoid CVSS score: 7.8 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: unknown Paranoid ActionableScore: 5 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: YES Published priority for this report (same as in Subject): MODERATE 7.0 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).