From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-64330][MODERATE REGULAR] usb: typec: tcpm: Validate SVID index in svdm_consume_modes() Date: Sat, 25 Jul 2026 11:31:54 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-64330 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: 4 X-AL-KERNEL-ActionableScore-Lower: 3 X-AL-KERNEL-Commit: 89ff289cbf5d3b659a2babc5ccaae4eaf7e7cf53 List-Id: CVE: CVE-2026-64330 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: usb: typec: tcpm: Validate SVID index in svdm_consume_modes() Commit: 89ff289cbf5d3b659a2babc5ccaae4eaf7e7cf53 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=89ff289cbf5d3b659a2babc5ccaae4eaf7e7cf53 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64330 Analysis date: Sat, 25 Jul 2026 11:31:54 -0400 ActionableScore: 4 ActionableScore lower bound: 3 Actionable bucket: Borderline Moderate, manual review recommended Manual review required: YES Summary: A malicious USB Type C PD partner can trigger an out of bounds read in TCPM SVDM mode handling and cause unintended alternate mode registration, but the issue is physical access only and does not show a strong memory corruption or privilege escalation primitive. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-64330 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64330 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-2026-64330 MODERATE CHECK WITH IMPACT FROM ORIG NN MODERATE Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:P/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L';CWE-125;CWE-129;*CWE-20;Other CVSS 'AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N';BEST CVSS score: '4.3';DESCR 'An out-of-bounds read in the USB Type C TCPM SVDM mode handling path can occur because svdm_consume_modes uses pmdata svid_index to read pmdata svids without first checking that the index is within the discovered SVID count. A malicious connected USB Type C PD partner can influence discovery state and make the host load an SVID value from adjacent pd_mode_data fields, including partner supplied mode data, which can result in registration of an unintended alternate mode. For the CVSS the PR:N because the attacker does not need a host account and only needs to act as the connected PD partner. The issue is not network reachable. Impact is primarily integrity policy confusion in the Type C alternate mode registration path, with limited confidentiality or availability impact only in a conservative review scenario.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline Moderate, manual review recommended (with actual score 4) YES REMOTE READ OOB USB NETWORK HARDWARE DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=4 ActionableScoreLower=3 ## 1. ActionableScore * Conservative score: 3 * Paranoid score: 4 * Final recommended bucket: **Borderline Moderate, manual review recommended** ## 2. Signal breakdown Conservative signals: * Firmware or device mediated external influence: +1. A malicious USB Type C PD partner can influence SVDM discovery state over the physical Type C connection. * Memory corruption, weak or indirect corruption candidate: +1. This is an out of bounds read from an embedded struct field, not an OOB write or UAF. * Integrity impact plausible: +1. The attacker can cause registration of an unintended alternate mode by steering the SVID value. * Broad or common hardware interface exposure: +1. USB Type C TCPM is common on many client and embedded systems. * Physical only or hardware attached condition: -2. The attacker needs a connected Type C PD partner or malicious accessory, not network access. Paranoid additional signal: * Confidentiality or availability concern in conservative review scenario: +1. The OOB read is not directly disclosed, but it reads adjacent kernel state and affects device registration behavior, so limited secondary impact deserves manual review. Not counted: * No remote network reachability. * No strong memory corruption primitive. * No OOB write, UAF, double free, arbitrary write, callback control, or reclaim primitive. * No demonstrated privilege escalation path. ## 3. Reachability analysis The bug is triggerable by a physically connected or otherwise controlled USB Type C PD partner that can manipulate SVDM Discovery Modes responses and drive `svid_index` beyond the valid SVID array range. No local account on the victim is required, but physical or device level access is required. Namespaces and containers do not materially affect reachability because the trigger is in the USB Type C PD negotiation path, not a local syscall or namespaced control plane. The path is relevant only on systems using the TCPM Type C stack and compatible hardware, but that is common enough on laptops, docks, embedded devices, phones, and USB C capable systems. ## 4. Severity interpretation This behaves like a borderline Moderate issue rather than an Important vulnerability. The patch and description show a real OOB read and an attacker influenced logic outcome, namely unintended alternate mode registration. However, the primitive is read only, physically mediated, and does not show memory disclosure to userspace, kernel memory overwrite, object lifetime corruption, or a practical LPE chain. The paranoid score is higher because the malformed SVID can be partner chosen and affects kernel device registration state, but the evidence still does not support Important class handling. Call-site confidence: medium. The provided description gives the downstream effect through `typec_partner_register_altmode()`, but the full surrounding call graph is not included. ## 5. One-sentence report phrase A malicious USB Type C PD partner can trigger an out of bounds read in TCPM SVDM mode handling and cause unintended alternate mode registration, but the issue is physical access only and does not show a strong memory corruption or privilege escalation primitive. ## 6. Manual review recommendation MANUAL CHECK RECOMMENDED Reason: the issue is externally device triggered and includes an OOB read with attacker influenced alternate mode registration, so it should not be blindly auto closed, but the current evidence supports Borderline Moderate rather than Actionable Moderate or Important. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: usb: typec: tcpm: Validate SVID index in svdm_consume_modes() Commit: 89ff289cbf5d3b659a2babc5ccaae4eaf7e7cf53 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=89ff289cbf5d3b659a2babc5ccaae4eaf7e7cf53 Commit description: In svdm_consume_modes(), the SVID value is read from pmdata->svids using pmdata->svid_index as an array index without bounds validation: paltmode->svid = pmdata->svids[pmdata->svid_index]; If pmdata->svid_index is driven beyond SVID_DISCOVERY_MAX (16), it results in an out-of-bounds read of the pmdata->svids array. Because pd_mode_data is embedded inside struct tcpm_port, indexing past svids reads into adjacent fields. In particular: - At index 16, it reads the altmodes count. - At index 18 and beyond, it reads into altmode_desc[], which contains partner-supplied SVDM Discovery Modes VDOs. By injecting a chosen SVID into altmode_desc[0].vdo and driving svid_index to 20, the partner can force paltmode->svid to be loaded with an arbitrary, partner- chosen SVID, which is then registered via typec_partner_register_altmode(). Fix this by validating that pmdata->svid_index is non-negative and strictly less than pmdata->nsvids before accessing the pmdata->svids array inside svdm_consume_modes(). Assisted-by: Antigravity:gemini-3.5-flash Fixes: 4ab8c18 ("usb: typec: Register a device for every mode") Cc: stable Signed-off-by: Badhri Jagan Sridharan Reviewed-by: RD Babiera Acked-by: Heikki Krogerus Link: https://patch.msgid.link/20260622220803.305750-1-badhri@google.com Signed-off-by: Greg Kroah-Hartman Changed files: drivers/usb/typec/tcpm/tcpm.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=89ff289cbf5d3b659a2babc5ccaae4eaf7e7cf53 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-64330 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64330 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:P/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N The Best / paranoid CVSS vector: AV:P/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L The Best / paranoid CVSS score: 4.3 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: 3 Paranoid ActionableScore: 4 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).