From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-72273][LOW] fbdev: efifb: fix memory leak in efifb_probe() [ Upstream Date: Sat, 15 Aug 2026 09:23:30 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-72273 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: fafb2e08741b20027cee77918816de29a32d6fd6 List-Id: CVE: CVE-2026-72273 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: fbdev: efifb: fix memory leak in efifb_probe() [ Upstream Commit: fafb2e08741b20027cee77918816de29a32d6fd6 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fafb2e08741b20027cee77918816de29a32d6fd6 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72273 Analysis date: Sat, 15 Aug 2026 09:23:30 -0400 ActionableScore: 0 ActionableScore lower bound: unknown Actionable bucket: Ordinary Moderate / Low-like Manual review required: NO Summary: No one-sentence report phrase was found. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-72273 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72273 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-2026-72273 LOW CHECK WITH IMPACT FROM ORIG NN MODERATE 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:L';*CWE-401;*CWE-772;CWE-404;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:N';BEST CVSS score: '1.9';DESCR 'efifb_probe leaked the option string returned by fb_get_options because ownership was transferred to the caller but the efifb path did not free it after setup. This is a small memory leak in the framebuffer probe path, not a memory corruption bug, and there is no evident UAF, OOB access, information leak, or privilege escalation primitive. For the CVSS the PR:H is used because reliable triggering normally requires administrative control over boot video options or privileged driver reprobe behavior. The issue is not network reachable and practical impact is negligible to low availability impact only.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 0) YES LEAK UAF LINUS DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_GUESSCVSS YES NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=0 1. ActionableScore * Conservative score: 0 * Paranoid score: 0 * Final recommended bucket: **Ordinary Moderate / Low-like**:: 2. Signal breakdown * No remote reachability: efifb_probe is not network-triggerable. * No local unprivileged trigger: reliable triggering normally requires boot option control or privileged driver reprobe behavior. * No memory corruption signal: the patch only adds kfree(option) for an ownership-transfer leak. No UAF, OOB, double-free, type confusion, stale callback, or write primitive is indicated. * No reliable strong DoS: this appears to be a small probe-path leak, not a realistic fast resource-exhaustion primitive. * Requires admin/root-like control in typical deployments: -2, but the final score is floored at 0. * Call-site confidence: high, because the affected allocation use and missing free are visible in the provided probe path. 3. Reachability analysis The bug is reachable during efifb platform framebuffer probing after fb_get_options returns an option string. Ordinary users cannot normally trigger repeated efifb_probe execution or control early video boot options. Containers and namespaces do not materially lower the privilege requirement because framebuffer platform device probing and boot option handling are host-level operations. The path may exist on EFI framebuffer systems, but the vulnerable condition is a small cleanup omission during probe, not a broadly exposed runtime interface. 4. Severity interpretation This behaves like a Low or ordinary Moderate cleanup issue, not an actionable Moderate or Important-class kernel vulnerability. The realistic impact is negligible to very low availability impact from a small memory leak. There is no supported theoretical memory corruption primitive and no evidence of privilege escalation, confidentiality impact, integrity impact, or remotely reachable attack surface. 5. One-sentence report phrase efifb_probe failed to free the option string returned by fb_get_options after setup, causing a small privileged probe-path memory leak without evidence of memory corruption, privilege escalation, or network reachability. 6. Manual review recommendation NO MANUAL CHECK NEEDED. This can be auto-closed for triage purposes because it is a small privileged memory leak with no realistic security boundary bypass, no strong DoS, and no memory corruption primitive. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: fbdev: efifb: fix memory leak in efifb_probe() [ Upstream Commit: fafb2e08741b20027cee77918816de29a32d6fd6 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fafb2e08741b20027cee77918816de29a32d6fd6 Changed files: drivers/video/fbdev/efifb.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=fafb2e08741b20027cee77918816de29a32d6fd6 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-72273 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72273 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:N The Best / paranoid CVSS vector: AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L The Best / paranoid CVSS score: 1.9 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: 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).