From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-64171][LOW] i2c: tegra: fix pm_runtime leak on mutex_lock failure Date: Sun, 19 Jul 2026 15:14:31 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-64171 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: 1 X-AL-KERNEL-ActionableScore-Lower: 0 X-AL-KERNEL-Commit: 8f7ed203b39004c02479a9156089d87d1ac2c1d8 List-Id: CVE: CVE-2026-64171 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: i2c: tegra: fix pm_runtime leak on mutex_lock failure Commit: 8f7ed203b39004c02479a9156089d87d1ac2c1d8 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8f7ed203b39004c02479a9156089d87d1ac2c1d8 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64171 Analysis date: Sun, 19 Jul 2026 15:14:31 -0400 ActionableScore: 1 ActionableScore lower bound: 0 Actionable bucket: Ordinary Moderate / Low-like auto-close candidate Manual review required: NO Summary: A missing pm_runtime_put() on the Tegra I2C mutex-lock failure path can leak a runtime PM reference and prevent runtime suspend, causing limited local availability or power-management impact without memory corruption or privilege escalation. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-64171 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64171 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-2026-64171 LOW 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:L';*CWE-772;CWE-404;CWE-459;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '3.3';DESCR 'The i2c tegra transfer path can leak a runtime PM reference when pm_runtime_get_sync() succeeds but tegra_i2c_mutex_lock() fails. The leaked reference can keep the I2C controller active and prevent runtime suspend, causing a power management and availability degradation rather than memory corruption. For the CVSS the PR:L is used for the paranoid score because a local process with access to an exposed I2C interface or a delegated device access path may be able to trigger transfers, but reliable triggering also depends on the mutex lock failure condition. The issue is not network reachable. Impact is limited denial of service for power management or device suspend behavior, with no supported path to information disclosure or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like auto-close candidate (with actual score 1) SKIP CVE-2026-64171 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: 6077cfd716fbd4d1f2a3702e49ae8bf65c072685 YES NO NO unknown MAYBE USB SIMPLEFIX LEAK HARDWARE LINUS - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=1 ActionableScoreLower=0 ## 1. ActionableScore * Conservative score: 0 * Paranoid score: 1 * Final recommended bucket: **Ordinary Moderate / Low-like auto-close candidate**:: ## 2. Signal breakdown * Availability impact realistic: +1. A leaked runtime PM reference can keep the Tegra I2C controller active and prevent runtime suspend. * Local unprivileged trigger: +1 only in the paranoid interpretation. This requires a local process with access to an exposed I2C interface or delegated device access. * Hard or unreliable condition: -1. The leak requires tegra_i2c_mutex_lock() to fail after pm_runtime_get_sync() succeeds. * Rare hardware or platform-specific path: -1. This is specific to the Tegra I2C controller path. * No memory corruption: +0. The patch fixes a missing pm_runtime_put(), not UAF, OOB, double free, refcount takeover, or object confusion. * No privilege escalation plausible: +0. There is no supported path to LPE. * No network reachability: +0. The issue is local/device-path only. * Call-site confidence: high. The affected function and error path are visible in the provided diff. ## 3. Reachability analysis The bug can be triggered only through the Tegra I2C transfer path, and only when the SW mutex lock operation fails after runtime PM has been acquired. In typical deployments, direct I2C access is restricted to privileged users or selected service accounts, though some embedded systems may expose I2C devices to non-root local processes. Namespaces do not materially improve reachability unless device nodes are explicitly delegated into a container. The path is not network reachable and depends on Tegra hardware plus a specific error condition. ## 4. Severity interpretation This behaves like a Low-like or ordinary Moderate resource-management bug, not an Important-class vulnerability. The realistic impact is limited availability or power-management degradation for the affected controller. There is no evidence of memory corruption, sensitive-object access, privilege escalation, or cross-boundary bypass. The paranoid score only accounts for possible local access to an exposed I2C interface, but the impact remains limited. ## 5. One-sentence report phrase A missing pm_runtime_put() on the Tegra I2C mutex-lock failure path can leak a runtime PM reference and prevent runtime suspend, causing limited local availability or power-management impact without memory corruption or privilege escalation. ## 6. Manual review recommendation NO MANUAL CHECK NEEDED This can be auto-closed for security triage unless the product exposes Tegra I2C access broadly to untrusted local users and treats persistent runtime-suspend failure as a high operational risk. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: i2c: tegra: fix pm_runtime leak on mutex_lock failure Commit: 8f7ed203b39004c02479a9156089d87d1ac2c1d8 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8f7ed203b39004c02479a9156089d87d1ac2c1d8 Commit description: If tegra_i2c_mutex_lock() fails, the function returns without calling pm_runtime_put(), leaking the runtime PM reference acquired by the preceding pm_runtime_get_sync(). This prevents the device from ever entering runtime suspend. Add the missing pm_runtime_put() before returning on lock failure. Fixes: 6077cfd ("i2c: tegra: Add support for SW mutex register") Signed-off-by: Saurav Sachidanand Cc: # v7.0+ Reviewed-by: Jon Hunter Acked-by: Thierry Reding Signed-off-by: Andi Shyti Link: https://lore.kernel.org/r/20260507221145.62183-2-sauravsc@amazon.com Signed-off-by: Greg Kroah-Hartman Changed files: drivers/i2c/busses/i2c-tegra.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=8f7ed203b39004c02479a9156089d87d1ac2c1d8 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-64171 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-64171 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:L/PR:L/UI:N/S:U/C:N/I:N/A:L The Best / paranoid CVSS score: 3.3 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: 0 Paranoid ActionableScore: 1 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).