From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-68248][MODERATE REGULAR] drm/i915: Return NULL on error in active_instance Date: Mon, 10 Aug 2026 18:00:18 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-68248 X-AL-KERNEL-Priority: MODERATE REGULAR X-AL-KERNEL-Severity: MODERATE REGULAR X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 3 X-AL-KERNEL-ActionableScore-Lower: 2 X-AL-KERNEL-Commit: 32c1a2afa90dd07df931f0b12578de1dbb751f0c List-Id: CVE: CVE-2026-68248 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: drm/i915: Return NULL on error in active_instance Commit: 32c1a2afa90dd07df931f0b12578de1dbb751f0c Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=32c1a2afa90dd07df931f0b12578de1dbb751f0c Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68248 Analysis date: Mon, 10 Aug 2026 18:00:18 -0400 ActionableScore: 3 ActionableScore lower bound: 2 Actionable bucket: Borderline Ordinary Moderate. Not an Important candidate Manual review required: NO Summary: A local user with access to the i915 DRM interface may trigger an allocation-failure path where `active_instance()` returns an invalid pointer derived from a NULL object, causing a kernel crash and denial of service. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68248 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68248 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 REGULAR 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-2026-68248 MODERATE 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-476;CWE-252;CWE-703;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.5';DESCR 'active_instance in the i915 driver could return an invalid pointer derived from node base when a GFP_ATOMIC allocation fails and node is NULL. A local process with access to the i915 DRM interface may then drive a later dereference of this invalid pointer, causing a kernel crash and denial of service. For the CVSS the PR:L is used because reliable triggering requires local code execution and access to the GPU device interface, which is commonly available through /dev/dri render nodes or device group policy. The issue is not network reachable. Impact is denial of service only. The patch context indicates NULL pointer dereference behavior rather than UAF, OOB write, or an arbitrary write primitive.';NO MANUAL CHECK; ,and ActionableScore result is Borderline Ordinary Moderate. Not an Important candidate (with actual score 3) YES LOCK SIMPLEFIX HARDWARE INCREASED_FROM_LOW_BASED_ON_HIGHCVSSSCORE DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5 YES NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=3 ActionableScoreLower=2 ## 1. ActionableScore * Conservative score: 2 * Paranoid score: 3 * Final recommended bucket: **Borderline Ordinary Moderate. Not an Important candidate**:: ## 2. Signal breakdown Conservative signals: * Local unprivileged trigger: +1. A local process with access to the i915 DRM interface may reach this path through normal GPU usage, often via `/dev/dri` render nodes. * Reliable kernel crash / strong DoS: +1. Returning `&node->base` when `node == NULL` can lead to an invalid pointer dereference and kernel crash. * Broad/default/common subsystem: +1. i915 is widely deployed on Intel GPU systems. * Hard or unreliable condition: -1. Triggering depends on a `GFP_ATOMIC` allocation failure, usually requiring memory pressure or a narrow allocator state. * Weak corruption only: +0. This is best treated as NULL/low-address invalid pointer dereference, not UAF, OOB write, arbitrary write, or object replacement. Paranoid difference: * The paranoid score does not subtract the hard-trigger condition, assuming a local user can make memory pressure and GPU activity sufficiently repeatable. No points awarded for: * Remote reachability. The path is local only. * Privilege escalation. No reclaim, overwrite, type confusion, callback control, or refcount takeover is shown. * Generic strong memory corruption. The patch fixes an invalid return value on allocation failure, not a demonstrated corruption primitive. * High-control GPU API bonus. The patch does not show attacker control over memory lifetime, callback targets, refcounts, DMA ownership, or object replacement. ## 3. Reachability analysis The likely trigger is a local process that can access the i915 DRM device and exercise the relevant active fence or execbuf-related path while a `GFP_ATOMIC` allocation fails. On many desktop systems, render nodes are available to ordinary local users through `/dev/dri/renderD*` or group policy, so PR:L is a reasonable CVSS interpretation. The issue is not network reachable. Containers only matter if the GPU device node is passed through or delegated into the container. In typical deployments without GPU device access, an untrusted container cannot trigger it directly. The path is common on Intel GPU systems, but the exact failure condition is OOM or atomic allocation failure, so exploit reliability is limited. ## 4. Severity interpretation This behaves like an ordinary Moderate local DoS. The theoretical bug is an invalid pointer return after allocation failure, but the realistic consequence is a kernel crash when that invalid pointer is later dereferenced. There is no evidence of UAF, double free, OOB write, arbitrary write, attacker-controlled reclaim, or type confusion. Therefore it should not be treated as an Important-class memory corruption issue based on the provided patch. ## 5. One-sentence report phrase A local user with access to the i915 DRM interface may trigger an allocation-failure path where `active_instance()` returns an invalid pointer derived from a NULL object, causing a kernel crash and denial of service. ## 6. Manual review recommendation MANUAL CHECK RECOMMENDED This is not urgent Important-class material, but a lightweight manual check is reasonable because i915 is widely deployed and local DRM access is often available to unprivileged users. The expected final disposition is local DoS only unless additional evidence shows a real memory corruption or privilege escalation primitive. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: drm/i915: Return NULL on error in active_instance Commit: 32c1a2afa90dd07df931f0b12578de1dbb751f0c Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=32c1a2afa90dd07df931f0b12578de1dbb751f0c Commit description: Avoid returning &node->base when node is NULL due to OOM during GFP_ATOMIC allocation. Discovered using AI-assisted static analysis confirmed by Intel Product Security. Reported-by: Martin Hodo Fixes: bfaae47 ("drm/i915: make lockdep slightly happier about execbuf.") Cc: Maarten Lankhorst Cc: Thomas Hellström Cc: Simona Vetter Cc: # v5.13+ Signed-off-by: Joonas Lahtinen Reviewed-by: Sebastian Brzezinka Reviewed-by: Maarten Lankhorst Link: https://patch.msgid.link/20260624090940.74840-1-joonas.lahtinen@linux.intel.com (cherry picked from commit 6029bc0 ) Signed-off-by: Joonas Lahtinen Signed-off-by: Greg Kroah-Hartman Changed files: drivers/gpu/drm/i915/i915_active.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=32c1a2afa90dd07df931f0b12578de1dbb751f0c ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68248 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68248 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: 2 Paranoid ActionableScore: 3 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: NO Published priority for this report (same as in Subject): MODERATE REGULAR 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).