From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-98003][LOW] iommu/amd: Do not reallocate GA log buffers on resume [ Upstream Date: Fri, 25 Sep 2026 14:58:27 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-98003 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: 94458b80d3b203c1c9e2c98aa7319b7713e006c0 List-Id: CVE: CVE-2026-98003 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: iommu/amd: Do not reallocate GA log buffers on resume [ Upstream Commit: 94458b80d3b203c1c9e2c98aa7319b7713e006c0 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=94458b80d3b203c1c9e2c98aa7319b7713e006c0 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98003 Analysis date: Fri, 25 Sep 2026 14:58:27 -0400 ActionableScore: 2 ActionableScore lower bound: 1 Actionable bucket: Ordinary Moderate Manual review required: NO Summary: No one-sentence report phrase was found. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-98003 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98003 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-2026-98003 LOW https://www.kernelcve.org/list/?q=CVE-2026-98003 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:L/I:L/A:H';*CWE-401;CWE-415;*CWE-416;**CWE-400;CWE-415;*CWE-416;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.8';DESCR 'AMD IOMMU GA log buffers can be allocated again on every system resume because iommu_init_ga_log is invoked from the virtual APIC enablement path and overwrites existing buffer pointers. Repeated suspend and resume cycles can therefore leak kernel memory and eventually cause resource exhaustion. A partial allocation failure can also leave a stale pointer after the allocated GA log buffer is freed, creating a possible double free or use after free cleanup condition that requires manual verification. For the CVSS the PR:L is selected for the paranoid score because a local user may be able to initiate suspend resume cycles through permitted desktop or service policy, although many server deployments require administrative power management privileges. The issue is not network reachable. Impact is primarily local denial of service, while limited confidentiality or integrity impact is conservatively retained only for the stale pointer error path.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 2) YES SIMPLEFIX LEAK LOG HARDWARE NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=2 ActionableScoreLower=1 PrimitiveClass=CLASS_C RealUAF=NO HostAdminRequired=UNKNOWN NamespaceScopedPrivilege=UNKNOWN ImportantCandidate=NO ManualReview=RECOMMENDED AutoDowngradeAllowed=YES 1. ActionableScore * Raw conservative score: 1 * Conservative score: 1 * Raw paranoid score: 2 * Paranoid score: 2 * Final recommended bucket: **Ordinary Moderate**:: No floor or cap was applied. 2. Signal breakdown Conservative signals: * +1 Concrete persistent kernel resource leak. Each resume can replace the existing GA log and GA log tail pointers without freeing the prior allocations. Repeated suspend resume activity can accumulate unrecoverable kernel allocations. Paranoid-only signal: * +1 Weak invalid lifetime state. The partial allocation error path can free ga_log while leaving iommu->ga_log non-NULL. The patch clears this field, directly confirming prevention of a dangling pointer state. However, no supplied caller or control flow establishes a later dereference, second free, or refcount mutation through that pointer. Non-awarded signals: * No Real UAF signal. A freed pointer remaining stored is not by itself a UAF. The supplied patch does not establish a subsequent stale dereference or stale release. * No concrete repeated release/refcount signal. The first free may occur in partial allocation cleanup, but a second lifetime-mutating operation on the exact same pointer is not shown. * No controlled reclaim, object replacement, arbitrary write, information disclosure, integrity violation, callback control, or privilege escalation is demonstrated. * No reliable kernel crash is established. * No remote reachability is established. * No local unprivileged trigger point is awarded. The input only suggests that a local user may be able to trigger suspend resume through deployment-specific policy, not that the complete vulnerable path is available to an ordinary user. * No host-admin penalty is applied because host-admin-equivalent privilege is not positively established. * No rare hardware penalty is applied. AMD IOMMU and AVIC related configuration are prerequisites, but the supplied evidence does not establish that an attacker cannot reach a configured affected machine. 3. Reachability analysis The affected path is reached during system resume when AMD IOMMU virtual APIC support invokes iommu_init_ga_log. The vulnerable system must have the relevant AMD IOMMU, IRQ remapping, and guest interrupt remapping or AVIC support enabled. The supplied evidence does not establish who can reliably trigger repeated suspend resume cycles. On many server systems, suspend and resume control is administrative. On some desktop or service-managed systems, a local user may be permitted to request suspend through policy. Therefore HostAdminRequired is UNKNOWN rather than YES or NO. No network namespace, user namespace, delegated capability, or namespace-scoped complete trigger chain is shown. NamespaceScopedPrivilege is UNKNOWN. The issue is not directly network reachable. 4. Primitive and severity interpretation The primary established defect is a repeatable memory leak caused by replacing GA log buffer pointers during resume. This is a resource-management issue and can cause availability degradation only after repeated resume cycles. The patch also prevents a stale pointer from remaining after partial allocation cleanup. This is an invalid lifetime state, but the supplied diff does not establish the required second stage for a real UAF or double-free: a later dereference, free, put, refcount decrement, or structured use of the same stale pointer. This is not an active structured-object UAF and not a concrete repeated lifetime mutation. The demonstrated primitive is therefore CLASS_C rather than CLASS_B. The practical consequence supported by the patch is memory leakage and potential resource exhaustion. A double-free or use-after-free is speculative without visible post-failure call sites. ImportantCandidate is NO because meaningful post-lifetime exploitation leverage is not established. AutoDowngradeAllowed is YES because the currently supported impact is a resource leak plus a stale-pointer prevention fix, without demonstrated stale consumption or corruption. 5. One-sentence report phrase Repeated system resume can leak AMD IOMMU GA log allocations, while a partial allocation failure can leave a stale GA log pointer that requires call-site review for possible later cleanup reuse. 6. Manual review recommendation MANUAL CHECK RECOMMENDED Review the iommu_init_ga_log error callers and all later free_ga_log call sites to determine whether a failed partial allocation can reach a second iommu_free_pages call on the same stale ga_log pointer. 7. Call-site confidence Call-site confidence: medium ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: iommu/amd: Do not reallocate GA log buffers on resume [ Upstream Commit: 94458b80d3b203c1c9e2c98aa7319b7713e006c0 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=94458b80d3b203c1c9e2c98aa7319b7713e006c0 Changed files: drivers/iommu/amd/init.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=94458b80d3b203c1c9e2c98aa7319b7713e006c0 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-98003 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98003 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:L The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H The Best / paranoid CVSS score: 5.8 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: 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).