From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-43330][MODERATE REGULAR] crypto: caam - fix overflow on long hmac keys [ Upstream Date: Thu, 21 May 2026 07:25:04 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-43330 X-AL-KERNEL-Priority: MODERATE REGULAR X-AL-KERNEL-Severity: MODERATE REGULAR X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 4 X-AL-KERNEL-ActionableScore-Lower: 3 X-AL-KERNEL-Commit: 31022cfde5235c45fa765f0aabeff5f0652852f2 List-Id: CVE: CVE-2026-43330 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: crypto: caam - fix overflow on long hmac keys [ Upstream Commit: 31022cfde5235c45fa765f0aabeff5f0652852f2 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=31022cfde5235c45fa765f0aabeff5f0652852f2 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-43330 Analysis date: Thu, 21 May 2026 07:25:04 -0400 ActionableScore: 4 ActionableScore lower bound: 3 Actionable bucket: Borderline, manual review recommended Manual review required: YES Summary: A local out of bounds read in the CAAM HMAC setkey path can occur when a long key is copied using a DMA aligned length instead of the real key length, with impact limited to a constrained kernel overread or possible DoS on CAAM enabled systems. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-43330 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-43330 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: MODERATE REGULAR 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-2026-43330 MODERATE CHECK Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H';CWE-126;CWE-125;CWE-119;Other CVSS 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '6.1';DESCR 'A local out of bounds read can occur in the CAAM HMAC setkey path when a long key is copied with a DMA aligned length instead of the real key length. The source key buffer has only keylen bytes, but kmemdup was asked to read aligned_len bytes, so adjacent kernel memory may be read into a temporary driver buffer. For the CVSS the PR:L is used because a local process may be able to reach the crypto setkey path through the kernel crypto API or AF_ALG when the CAAM algorithm is available. The issue is not network reachable and depends on CAAM hardware and driver configuration. Impact is mainly local denial of service or a weak confidentiality concern from an overread, but the patch does not show an attacker controlled write, UAF reclaim, or reliable privilege escalation primitive.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline, manual review recommended (with actual score 4) MAYBE SIMPLEFIX DMAorINTERRUPT LINUS INCREASED_FROM_LOW_BASED_ON_REQUIREMANUALCHECK DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5 - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=4 ActionableScoreLower=3 ## 1. ActionableScore * Conservative score: 3 * Paranoid score: 4 * Final recommended bucket: **Borderline, manual review recommended**:: ## 2. Signal breakdown * Local unprivileged trigger: +1 The path may be reachable by a local process through the kernel crypto API or AF_ALG if the CAAM HMAC algorithm is registered and accessible. * Local unprivileged high-control kernel data-plane API: +1 AF_ALG and crypto setkey operations can give local users control over key length and key contents. * Privileged kernel/device-management memory safety path: +1 The bug is in a hardware crypto driver and involves DMA alignment handling in a trusted kernel driver path. * Confidentiality impact plausible: +1 paranoid only `kmemdup(key, aligned_len)` reads beyond the provided `keylen` source buffer. This is a kernel overread, but the patch does not show a reliable user-visible disclosure path. * Availability impact possible: +1 paranoid only The overread may trigger KASAN reports or faults in unlucky layouts, but a reliable production kernel crash is not strongly demonstrated. * Rare hardware/configuration dependency: -1 The affected path requires CAAM hardware and the relevant CAAM crypto driver and algorithm configuration. * Constrained primitive: -1 The primitive is a short read past the end of a source key buffer by DMA alignment padding size. There is no attacker-controlled overwrite target, UAF reclaim, arbitrary write, or page-cache corruption. ## 3. Reachability analysis The likely attacker is a local user or local process able to request an HMAC operation using the CAAM-backed ahash implementation. In common deployments this depends on whether CAAM hardware exists, whether the driver is enabled, and whether the algorithm is exposed through AF_ALG or another local crypto API user path. Namespaces do not materially improve reachability unless the crypto interface is available inside the container. The issue is not network reachable by itself. ## 4. Severity interpretation This behaves like a constrained local kernel overread in a hardware crypto driver, not like a strong memory corruption or privilege escalation primitive. The theoretical concern is that adjacent kernel memory is copied into a temporary buffer, but the patch does not demonstrate a reliable information leak, attacker-controlled write, UAF, or LPE path. This is therefore best treated as Borderline or low Actionable Moderate for manual review, not as a Strong Important candidate. ## 5. One-sentence report phrase A local out of bounds read in the CAAM HMAC setkey path can occur when a long key is copied using a DMA aligned length instead of the real key length, with impact limited to a constrained kernel overread or possible DoS on CAAM enabled systems. ## 6. Manual review recommendation MANUAL CHECK RECOMMENDED. This is a memory safety issue in a DMA-adjacent crypto driver path, but the primitive is read-only and constrained, with no demonstrated disclosure channel or privilege escalation path. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: crypto: caam - fix overflow on long hmac keys [ Upstream Commit: 31022cfde5235c45fa765f0aabeff5f0652852f2 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=31022cfde5235c45fa765f0aabeff5f0652852f2 Changed files: drivers/crypto/caam/caamalg_qi2.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=31022cfde5235c45fa765f0aabeff5f0652852f2 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-43330 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-43330 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:L/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:L/I:N/A:H The Best / paranoid CVSS score: 6.1 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: 3 Paranoid ActionableScore: 4 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: MODERATE KPANIC detected for this report: NO Published priority for this report (same as in Subject): MODERATE REGULAR 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).