From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-72275][LOW] fbdev: broadsheetfb: fix potential memory leak in broadsheetfb_probe() Date: Sun, 16 Aug 2026 06:37:55 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-72275 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: 0 X-AL-KERNEL-ActionableScore-Lower: unknown X-AL-KERNEL-Commit: edc5a845108337d0c167ab850fe9adfaea442975 List-Id: CVE: CVE-2026-72275 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: fbdev: broadsheetfb: fix potential memory leak in broadsheetfb_probe() Commit: edc5a845108337d0c167ab850fe9adfaea442975 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=edc5a845108337d0c167ab850fe9adfaea442975 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72275 Analysis date: Sun, 16 Aug 2026 06:37:55 -0400 ActionableScore: 0 ActionableScore lower bound: unknown Actionable bucket: Ordinary Moderate / Low-like Manual review required: NO Summary: A privileged local probe error path in broadsheetfb can leak deferred IO pageref memory, but exploitation requires administrative control over driver probing and the issue has no demonstrated memory corruption or privilege escalation primitive. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-72275 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72275 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-2026-72275 LOW 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:H/UI:N/S:U/C:N/I:N/A:H';*CWE-401;*CWE-772;CWE-703;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.1';DESCR 'broadsheetfb_probe() can leak deferred IO pageref memory when fb_deferred_io_init() succeeds but a later probe step fails. This is a probe error path resource leak rather than a memory corruption bug, and no UAF, OOB access, or arbitrary write primitive is indicated by the code change. For the CVSS the PR:H is used because reliable triggering typically requires administrative control over driver binding, device probing, or platform device setup. The issue is not network reachable. Impact is mainly local denial of service through resource exhaustion, but practical impact is low because the leak depends on repeated failed probe paths and does not directly affect confidentiality or integrity.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 0) SKIP CVE-2026-72275 UNKNOWN SKIP No affected files built, so skip this CVE NO - - unknown MAYBE INIT LEAK ERRORPATH UAF LINUS - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=0 ## 1. ActionableScore * Conservative score: 0 * Paranoid score: 0 * Final recommended bucket: **Ordinary Moderate / Low-like**:: ## 2. Signal breakdown Triggered or considered signals: * Availability impact realistic: +0 The bug is a memory leak on a probe error path, but the patch does not show an immediate or reliable system-wide DoS condition. * Requires admin/root/CAP_* in typical deployments: -2 Reliable triggering normally requires administrative control over driver probing, platform-device setup, driver binding, or forced probe-failure conditions. * Rare AND difficult-to-reach subsystem/configuration: -1 broadsheetfb is a niche fbdev driver path and not a broadly exposed default attack surface. * Memory corruption: +0 No UAF, double free, OOB access, arbitrary write, stale callback, refcount takeover, or attacker-controlled object reuse is indicated. * Privilege escalation plausible: +0 The leak is limited to deferred IO pageref cleanup on an initialization error path and does not provide a credible LPE primitive. Effective score is floored at 0. ## 3. Reachability analysis The issue is local and privileged in realistic deployments. An attacker would need the ability to cause or repeat broadsheetfb device probe attempts and also hit a later initialization failure after `fb_deferred_io_init()` succeeds. Namespaces or containers do not normally expose this path to an unprivileged user. The affected subsystem is not network reachable and is tied to a specific framebuffer driver and hardware or platform-device configuration. Call-site confidence: high. The relevant probe error path and cleanup labels are present in the supplied patch. ## 4. Severity interpretation This behaves like a Low-like or ordinary Moderate resource-leak bug, not an actionable Moderate or Important-class vulnerability. The theoretical impact is memory exhaustion if a privileged actor can repeatedly force the failing probe path, but realistic exploitation evidence is weak. There is no demonstrated memory corruption, confidentiality impact, integrity impact, or privilege-escalation path. ## 5. One-sentence report phrase A privileged local probe error path in broadsheetfb can leak deferred IO pageref memory, but exploitation requires administrative control over driver probing and the issue has no demonstrated memory corruption or privilege escalation primitive. ## 6. Manual review recommendation NO MANUAL CHECK NEEDED This can be auto-closed for urgent triage purposes because it is a privileged, niche driver probe-path memory leak with no concrete corruption primitive and no network or unprivileged reachability. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: fbdev: broadsheetfb: fix potential memory leak in broadsheetfb_probe() Commit: edc5a845108337d0c167ab850fe9adfaea442975 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=edc5a845108337d0c167ab850fe9adfaea442975 Commit description: The memory allocated for pagerefs in fb_deferred_io_init() is not freed on the error path. Fix it by calling fb_deferred_io_cleanup(). Fixes: 56c134f ("fbdev: Track deferred-I/O pages in pageref struct") Cc: stable@vger.kernel.org Signed-off-by: Abdun Nihaal Reviewed-by: Thomas Zimmermann Signed-off-by: Helge Deller Signed-off-by: Greg Kroah-Hartman Changed files: drivers/video/fbdev/broadsheetfb.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=edc5a845108337d0c167ab850fe9adfaea442975 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-72275 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72275 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:H/UI:N/S:U/C:N/I:N/A:L The Best / paranoid CVSS vector: AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H The Best / paranoid CVSS score: 4.1 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: 0 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).