From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-72064][MODERATE REGULAR] net: mana: Sync page pool RX frags for CPU Date: Sat, 15 Aug 2026 21:37:28 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-72064 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: bc650dd5ce6434286b96e2b26a41af81f679cc7c List-Id: CVE: CVE-2026-72064 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: net: mana: Sync page pool RX frags for CPU Commit: bc650dd5ce6434286b96e2b26a41af81f679cc7c Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bc650dd5ce6434286b96e2b26a41af81f679cc7c Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72064 Analysis date: Sat, 15 Aug 2026 21:37:28 -0400 ActionableScore: 3 ActionableScore lower bound: 2 Actionable bucket: Borderline manual review recommended / Ordinary Moderate otherwise Manual review required: YES Summary: A missing sync-for-CPU operation for MANA page pool RX fragments can allow remote traffic to cause stale or corrupted packet data to be processed on DMA configurations requiring explicit synchronization, leading primarily to RX failure or denial of service. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-72064 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72064 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: YES A detailed explanation of the methodology and priority rules is included at the end of this message. ====================================================================== AL-KERNEL CLASSIFICATION RESULT ====================================================================== CVE-2026-72064 MODERATE CHECK WITH IMPACT FROM ORIG NN LOW Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H';CWE-662;*CWE-664;CWE-755;Other CVSS 'AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.9';DESCR 'MANA RX buffers allocated as page pool fragments can remain DMA mapped and skip the implicit sync for CPU that normally happens through dma_unmap_single. On systems that require explicit DMA synchronization, such as swiotlb forced configurations or DMA incoherent paths, packet bytes may be read by the CPU before the received range is synchronized. A remote peer can trigger the affected RX path by sending traffic to the MANA interface, but reliable impact depends on platform DMA behavior and whether page pool RX fragments are used. For the CVSS the PR:N because no local account is needed if the attacker can reach the network interface. Impact is primarily denial of service or broken RX behavior through stale or corrupted packet data, with no clear UAF, OOB write, or privilege escalation primitive shown by the code change.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline manual review recommended / Ordinary Moderate otherwise (with actual score 3) YES REMOTE NETWORK DMAorINTERRUPT HARDWARE MEMORY PACKET 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 manual review recommended / Ordinary Moderate otherwise**:: ## 2. Signal breakdown Conservative signals: * Remote reachable / network-triggerable: +2. A remote peer can exercise the RX path by sending traffic to the affected MANA interface. * Availability impact realistic: +1. On systems requiring explicit DMA sync, RX can break or process stale/corrupted packet bytes. * Rare AND difficult-to-reach subsystem/configuration: -1. The practical failure depends on MANA, page pool RX fragments, frag_count greater than 1, and DMA configurations such as swiotlb=force or incoherent DMA behavior. Paranoid additional interpretation: * Reliable kernel crash / strong DoS: +1 can be considered only as a paranoid availability signal if RX corruption makes the interface effectively unusable under sustained traffic. This is not supported as memory corruption or LPE. Not awarded: * No generic memory corruption. The patch fixes DMA coherency/sync, not UAF, double free, OOB write, type confusion, or arbitrary write. * No privilege escalation plausible. There is no reclaim, overwrite, callback, object confusion, or refcount takeover primitive. * No confidentiality or integrity impact. The patch supports stale or unsynchronized RX data, not a demonstrated information leak or attacker-controlled kernel write. ## 3. Reachability analysis A remote sender can trigger RX processing by sending packets to a reachable MANA interface, so PR:N is reasonable for network reachability. The issue is not in a common networking core path, but in the Microsoft MANA NIC driver. Exploitation depends on affected deployment details, especially page pool fragment use and a platform or boot configuration that requires explicit DMA synchronization. Namespaces do not materially reduce the privilege requirement because the trigger is packet reception, not a local control-plane API. Call-site confidence: high. The patch includes allocation, refill, RX completion, and the newly stored page pool sync metadata. ## 4. Severity interpretation This behaves like an ordinary Moderate to borderline actionable Moderate issue. The realistic impact is availability degradation or broken RX behavior on specific MANA DMA configurations. The theoretical concern is that stale or corrupted packet data enters the networking stack, but the patch does not show a concrete memory corruption primitive, kernel crash path, data disclosure primitive, or privilege escalation path. ## 5. One-sentence report phrase A missing sync-for-CPU operation for MANA page pool RX fragments can allow remote traffic to cause stale or corrupted packet data to be processed on DMA configurations requiring explicit synchronization, leading primarily to RX failure or denial of service. ## 6. Manual review recommendation MANUAL CHECK RECOMMENDED Reason: network-triggerable RX-path bugs should not be auto-closed without checking product exposure, but the current patch supports availability impact only and does not justify Important-class handling. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: net: mana: Sync page pool RX frags for CPU Commit: bc650dd5ce6434286b96e2b26a41af81f679cc7c Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bc650dd5ce6434286b96e2b26a41af81f679cc7c Commit description: MANA allocates RX buffers from page pool fragments when frag_count is greater than 1. In that case the buffers remain DMA mapped by page pool and the RX completion path does not call dma_unmap_single(). As a result, the implicit sync-for-CPU normally performed by dma_unmap_single() is missing before the packet data is passed to the networking stack. This breaks RX on configurations which require explicit DMA syncing, for example when booted with swiotlb=force. Fix this by recording the page pool page and DMA sync offset when the RX buffer is allocated, and syncing the received packet range for CPU access before handing the RX buffer to the stack. Fixes: 730ff06 ("net: mana: Use page pool fragments for RX buffers instead of full pages to improve memory efficiency.") Cc: stable@vger.kernel.org Reviewed-by: Haiyang Zhang Signed-off-by: Dexuan Cui Link: https://patch.msgid.link/20260702041237.617719-3-decui@microsoft.com Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman Changed files: drivers/net/ethernet/microsoft/mana/mana_en.c include/net/mana/mana.h 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=bc650dd5ce6434286b96e2b26a41af81f679cc7c ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-72064 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72064 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:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L The Best / paranoid CVSS vector: AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS score: 5.9 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).