From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-98578][IMPORTANT] nfc: st21nfca: validate ISO15693 inventory length [ Upstream Date: Sat, 24 Oct 2026 06:05:33 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-98578 X-AL-KERNEL-Priority: IMPORTANT X-AL-KERNEL-Severity: IMPORTANT X-AL-KERNEL-Base-Severity: IMPORTANT X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 5 X-AL-KERNEL-ActionableScore-Lower: unknown X-AL-KERNEL-Commit: e47b2a350bb0ff123434ec5484c6dc3333b0727c List-Id: CVE: CVE-2026-98578 Priority: IMPORTANT AL-KERNEL base severity: IMPORTANT KPANIC flag: NO Patch: nfc: st21nfca: validate ISO15693 inventory length [ Upstream Commit: e47b2a350bb0ff123434ec5484c6dc3333b0727c Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e47b2a350bb0ff123434ec5484c6dc3333b0727c Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98578 Analysis date: Sat, 24 Oct 2026 06:05:33 -0400 ActionableScore: 5 ActionableScore lower bound: unknown Actionable bucket: Actionable Moderate / Strong Important candidate requiring manual review Manual review required: YES Summary: A malformed ISO15693 inventory response can underflow the UID-copy length and trigger an oversized kernel heap write, with crash proven plausible but stronger exploitation unresolved. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-98578 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98578 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: IMPORTANT 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-2026-98578 IMPORTANT https://www.kernelcve.org/list/?q=CVE-2026-98578 CHECK WITH IMPACT FROM ORIG NN LOW | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=2 LEGACY=IMPORTANT RESULT=DIFF INDEPENDENT_LEGACY=IMPORTANT INDEPENDENT_RESULT=DIFF TEMP_KPANIC_MERGE=IMPORTANT_WINS_DISAGREEMENT PRE_MERGE_LEGACY=IMPORTANT (final Legacy and Aegis differ; FINAL: IMPORTANT, Aegis: MODERATE_KPANIC) Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H';*CWE-20;CWE-125;CWE-191;*CWE-787;Other CVSS 'AV:A/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H';BEST CVSS score: '8.8';DESCR 'The ISO15693 inventory parser can accept a response with only one byte left after prefix removal and then read the second byte as the DSFID. The same short length can make the UID copy length underflow when it is calculated as the remaining length minus two, creating an out of bounds copy that can crash the kernel and may corrupt memory. A malicious ISO15693 tag within NFC range can provide the malformed response while the reader performs an inventory operation. For the CVSS the PR:N value is used because the attacker needs no operating system account or local privileges. The base UI:R value assumes that a user or application initiates scanning, while automatic reader polling supports UI:N in the paranoid vector. Automated impact decision path. The original SimpleNet classifier selected LOW. The primary LLM estimated paranoid CVSS 8.8 and the production ActionableScore returned 5 with recommendation Actionable Moderate / Strong Important candidate requiring manual review. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were CVSS and initial triage stage LOW to IMPORTANT because the CVSS score, vector or bug class threshold rule was applied. KP and FD specialist checks stage IMPORTANT to IMPORTANT because a specific evidence based protection or manual review veto was applied. final reconciliation stage IMPORTANT to IMPORTANT because KP specialist did not establish a qualifying panic. The legacy KP specialist produced a review artifact and its decision was processed by the applicable KP rules. The legacy FD or DH downgrade specialist produced a review artifact and its decision was processed by the applicable downgrade and preservation rules. Exact triggered rule markers were INCREASED_TO_HIGH_BASED_ON_GUESSCVSS8.5PLUS and V42_LEGACY_CLASSA_FD_VETO and MANUAL_REVIEW_REQUIRED and TEMP_KPANIC_MERGE_IMPORTANT_WINS and KPANIC_UNSUPPORTED_REMOVED. The independent weaker Aegis shadow evaluated CVSS 0.0 and ActionableScore 2 with primitive class CLASS_C and manual review REQUIRED. Its independently reconciled impact was MODERATE_KPANIC. Cross model aggregation changed the production result under an enabled evidence gated merge rule. The final reported impact is IMPORTANT.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate / Strong Important candidate requiring manual review (with actual score 5) MAYBE SIMPLEFIX SKB LINUS INCREASED_TO_HIGH_BASED_ON_GUESSCVSS8.5PLUS V42_LEGACY_CLASSA_FD_VETO MANUAL_REVIEW_REQUIRED TEMP_KPANIC_MERGE_IMPORTANT_WINS KPANIC_UNSUPPORTED_REMOVED - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=5 PrimitiveClass=CLASS_A RealUAF=NO HostAdminRequired=NO NamespaceScopedPrivilege=NO ImportantCandidate=YES ManualReview=REQUIRED AutoDowngradeAllowed=NO RequiresHostUID0=NO AuthorizationDecisionBypass=NO ProtectedResourceImpact=NONE B4PendingReview=NO B4PendingConfirmed=NO 1. ActionableScore * Raw base score: 4. * Conservative score: 5. Manual-review safety floor applied: 4 -> 5 for a concrete attacker-influenced heap OOB write. * Raw paranoid score: 4. * Paranoid score: 5. Same floor; no additional speculative effects scored. * Final recommended bucket: **Actionable Moderate / Strong Important candidate requiring manual review**:: 2. Signal breakdown * +2 — Strong corruption primitive: accepting `len == 1` after prefix removal makes the UID-copy length `len - 2` underflow, causing an oversized write beyond the destination UID storage. * +1 — Firmware/device-mediated external influence: a nearby malicious ISO15693 tag can supply the malformed inventory response. * +1 — Reliable kernel crash/strong DoS is plausible from the oversized copy and resulting invalid memory access. * No retry/re-entry accumulation exists; NEW52 B5-R does not apply. * No controlled target, arbitrary payload, named adjacent victim, disclosure, or LPE is shown. * No extra integrity or availability point: kernel memory corruption and its likely crash are already counted. * No remote-network bonus: NFC proximity is not ordinary remote reachability. * No physical/rare-hardware penalty: NFC hardware is required, but the evidence does not establish rare hardware or physical contact/access. 3. Reachability analysis The supported attacker is a nearby malicious NFC tag, requiring an NFC reader to perform inventory scanning. The supplied evidence describes no OS account, host UID 0, capability, namespace privilege, or host-administrator requirement. User/application initiation may be required; automatic polling is possible but not proven as the universal path. No timing race or retry sequence is involved. 4. Primitive and severity reading The primitive is an attacker-triggered heap/slab OOB write caused by unsigned copy-length underflow, not a UAF or read-only overrun. The destination is fixed and arbitrary target selection is not shown, but the copy is not harmlessly bounded. CLASS_A is appropriate for the concrete attacker-influenced OOB write. ImportantCandidate is retained because exploit leverage beyond crash is unresolved; AutoDowngradeAllowed is NO. B3-PENDING and B4-PENDING are inapplicable. 5. One-sentence report phrase A malformed ISO15693 inventory response can underflow the UID-copy length and trigger an oversized kernel heap write, with crash proven plausible but stronger exploitation unresolved. 6. Manual review advice MANUAL CHECK REQUIRED Concrete externally influenced kernel OOB write requires Important-versus-Moderate exploit-leverage review. 7. Call-site confidence Call-site confidence: medium ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: nfc: st21nfca: validate ISO15693 inventory length [ Upstream Commit: e47b2a350bb0ff123434ec5484c6dc3333b0727c Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e47b2a350bb0ff123434ec5484c6dc3333b0727c Changed files: drivers/nfc/st21nfca/core.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=e47b2a350bb0ff123434ec5484c6dc3333b0727c ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-98578 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98578 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:A/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H The Best / paranoid CVSS vector: AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H The Best / paranoid CVSS score: 8.8 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: 5 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: IMPORTANT KPANIC detected for this report: NO Published priority for this report (same as in Subject): IMPORTANT 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).