From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-99049][LOW] gpio: xilinx: fix runtime PM leak on request error path Date: Tue, 27 Oct 2026 01:19:28 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-99049 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: unknown X-AL-KERNEL-Commit: b07b3925f676640103b3d74b93fc401b1c873d13 List-Id: CVE: CVE-2026-99049 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: gpio: xilinx: fix runtime PM leak on request error path Commit: b07b3925f676640103b3d74b93fc401b1c873d13 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b07b3925f676640103b3d74b93fc401b1c873d13 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99049 Analysis date: Tue, 27 Oct 2026 01:19:28 -0400 ActionableScore: 1 ActionableScore lower bound: unknown Actionable bucket: Ordinary Moderate Manual review required: NO Summary: A failed Xilinx GPIO request leaks one runtime-PM usage reference, preventing controller suspension and leaving its clock enabled without demonstrated memory corruption or host-wide denial of service. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-99049 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99049 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-2026-99049 LOW https://www.kernelcve.org/list/?q=CVE-2026-99049 CHECK WITH IMPACT FROM ORIG NN LOW | AEGIS IMPACT LOW AEGIS_AS=1 LEGACY=LOW RESULT=SAME (final reconciliation agrees; DECISION: both 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:N/I:N/A:L';*CWE-772;CWE-404;BEST CVSS score: '2.5';DESCR 'The Xilinx GPIO request error path leaks a runtime PM usage reference because pm_runtime_get_sync increments the counter even when resume fails and gpiolib does not call xgpio_free after a failed request. The demonstrated primitive is persistent resource retention that prevents the affected controller from runtime suspending and leaves its clock enabled. For the CVSS the PR:L value reflects that a local user or process must be permitted to request GPIO lines, while successful triggering also requires a runtime PM resume failure. There is no supported UAF, OOB access, information disclosure, privilege escalation, or established host wide resource exhaustion path, so confidentiality and integrity remain none and availability is low. Automated impact decision path. The original SimpleNet classifier selected LOW. The primary LLM estimated paranoid CVSS 2.5 and the production ActionableScore returned 1 with recommendation Ordinary Moderate. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. No severity changing production threshold or specialist override was recorded. The legacy KP specialist has no review artifact for this run. The legacy FD or DH downgrade specialist has no review artifact for this run. The independent weaker Aegis shadow evaluated CVSS 2.5 and ActionableScore 1 with primitive class CLASS_C and manual review REQUIRED. Its independently reconciled impact was LOW. The shadow agreed with the final production impact and aggregation did not change that impact. The final reported impact is LOW.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1) MAYBE SIMPLEFIX LEAK ERRORPATH HARDWARE LINUS - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=1 PrimitiveClass=CLASS_C RealUAF=NO HostAdminRequired=NO NamespaceScopedPrivilege=NO ImportantCandidate=NO ManualReview=NO AutoDowngradeAllowed=YES RequiresHostUID0=NO AuthorizationDecisionBypass=NO ProtectedResourceImpact=NONE B4PendingReview=NO B4PendingConfirmed=NO 1. ActionableScore * Raw base score: 1. * Conservative score: 1; no floor or cap applied. * Raw paranoid score: 1. * Paranoid score: 1; no technically supported additional impact. * Final recommended bucket: **Ordinary Moderate**:: 2. Signal breakdown * +1 Concrete persistent kernel resource/reference leak: `pm_runtime_get_sync()` increments the runtime-PM usage counter even when resume fails; failed `->request()` receives no matching `->free()` or `pm_runtime_put()`. * +0 Availability: the controller cannot runtime-suspend and its clock remains enabled, but no controller failure, host-wide exhaustion, crash, or persistent service outage is shown. * No UAF, OOB access, memory corruption, repeated release, authorization bypass, confidentiality impact, or integrity impact is shown. * No retry-accumulated OOB write, shared-backing write, or authorization-state preservation profile applies. 3. Reachability analysis A local process permitted to request GPIO lines can reach `xgpio_request()`, but triggering the leak additionally requires runtime resume to fail. The supplied evidence supports below-host-admin GPIO access and does not require UID 0. This is device-node/resource permission, not a namespace-scoped capability. No race, special retry sequence, prior privileged configuration, or unusual hardware condition beyond use of the affected Xilinx GPIO controller is established. 4. Primitive and severity reading The exact primitive is a leaked runtime-PM usage reference on an error path. It retains power-management state and keeps the controller clock enabled; it neither frees storage nor accesses stale memory. This is CLASS_C device-local resource retention, with low power-management impact rather than a demonstrated security boundary or host availability primitive. ImportantCandidate is NO and auto-downgrade is allowed because no material unknown corruption or authorization primitive remains. 5. One-sentence report phrase A failed Xilinx GPIO request leaks one runtime-PM usage reference, preventing controller suspension and leaving its clock enabled without demonstrated memory corruption or host-wide denial of service. 6. Manual review advice NO MANUAL CHECK NEEDED The patch establishes a narrow runtime-PM reference leak with no Important-preserving primitive. 7. Call-site confidence Call-site confidence: high ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: gpio: xilinx: fix runtime PM leak on request error path Commit: b07b3925f676640103b3d74b93fc401b1c873d13 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b07b3925f676640103b3d74b93fc401b1c873d13 Commit description: pm_runtime_get_sync() leaves the usage counter incremented even when it fails, and xgpio_request() returns the error without dropping it. gpiolib does not call ->free() when ->request() fails, so xgpio_free(), which holds the only matching pm_runtime_put(), never runs. The reference is leaked and the controller can no longer runtime-suspend, so its clock stays enabled. Switch to pm_runtime_resume_and_get(), which only increments the usage counter on success. Fixes: 26b0477 ("gpio: gpio-xilinx: Add support for suspend and resume") Cc: stable@vger.kernel.org Signed-off-by: Ridham Khurana Link: https://patch.msgid.link/20260923113905.1409290-1-khurana.ridham222@gmail.com Signed-off-by: Bartosz Golaszewski Signed-off-by: Greg Kroah-Hartman Changed files: drivers/gpio/gpio-xilinx.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=b07b3925f676640103b3d74b93fc401b1c873d13 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-99049 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99049 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: Not available The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L The Best / paranoid CVSS score: 2.5 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: unknown 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).