From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-80708][MODERATE REGULAR] s390/zcrypt: Fix missing mem scrub at clear key import in cca_clr2cipherkey() [ Upstream Date: Fri, 28 Aug 2026 06:09:18 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-80708 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: 8e1c0def77b7450be0ed607ed0d7bae629d30020 List-Id: CVE: CVE-2026-80708 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: s390/zcrypt: Fix missing mem scrub at clear key import in cca_clr2cipherkey() [ Upstream Commit: 8e1c0def77b7450be0ed607ed0d7bae629d30020 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8e1c0def77b7450be0ed607ed0d7bae629d30020 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80708 Analysis date: Fri, 28 Aug 2026 06:09:18 -0400 ActionableScore: 4 ActionableScore lower bound: 3 Actionable bucket: Borderline / manual review recommended Manual review required: YES Summary: A missing memory scrub in s390/zcrypt CCA clear key import could leave clear AES key material in reusable CPRB buffers, creating a local confidentiality risk if the same kernel memory is later exposed through buffer reuse. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-80708 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80708 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-2026-80708 MODERATE 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:L/UI:N/S:U/C:H/I:N/A:N';CWE-226;*CWE-200;CWE-312;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N';BEST CVSS score: '4.7';DESCR 'A sensitive data exposure issue exists in s390/zcrypt because clear key material used during cca_clr2cipherkey() can remain in internal CPRB helper buffers after the clear key import flow completes. The stale data may include AES clear key material or related intermediate buffers and could be exposed later through tricky reuse of the same kernel memory or mempool backed object. For the CVSS the PR:L value is used because reliable triggering generally requires a local user or local process with access to the zcrypt CCA key import path, rather than unauthenticated network access. The issue is not network reachable and does not indicate memory corruption or code execution. Impact is confidentiality only, with the paranoid score treating key material exposure as high confidentiality impact.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline / manual review recommended (with actual score 4) YES SIMPLEFIX LINUS INCREASED_FROM_LOW_BASED_ON_REQUIREMANUALCHECK DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5 NO NO 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 Conservative signals: * Local unprivileged or low privileged trigger: +1 The affected path is local zcrypt CCA key import. It does not appear network reachable, but it can be reachable by a local process with access to the zcrypt interface. * Confidentiality impact plausible: +1 The stale buffer may contain clear AES key material or related intermediate key import data. * Sensitive secret exposure concern: +1 The data involved is cryptographic key material, which is more sensitive than ordinary kernel heap residue. I count this conservatively as a limited secret exposure concern because the patch does not show a direct generic read primitive. * Rare and platform specific subsystem: -1 This requires s390 zcrypt CCA clear key import behavior and relevant hardware or environment. Paranoid adjustment: * Sensitive key material exposure treated as high value: +1 additional In the paranoid interpretation, if the stale CPRB or mempool buffer can be reused in a way that exposes the previous contents, exposure of clear AES key material can be security significant even without memory corruption. No memory corruption, UAF, OOB write, double free, privilege escalation, or reliable DoS primitive is indicated by the patch. ## 3. Reachability analysis The bug is local to the s390 zcrypt CCA clear key import path. A realistic trigger requires a local process that can invoke the CCA clear key to secure key import functionality through the zcrypt stack or through a service using that stack. This is not remotely network triggerable by itself. Namespaces or containers do not automatically make this reachable. The relevant question is whether the zcrypt device or a key management service backed by zcrypt is exposed to less trusted local users or workloads. In typical deployments this is specialized hardware and configuration dependent, but the data involved is sensitive cryptographic material. ## 4. Severity interpretation This behaves like an information exposure issue, not a memory corruption or DoS issue. The realistic impact is possible confidentiality loss of clear key material through reuse of uncleared internal buffers. The patch does not support integrity impact, privilege escalation, arbitrary read, arbitrary write, or code execution. The conservative result is borderline Moderate because the exposure path is indirect and platform specific. The paranoid result is still worth manual review because cryptographic clear key material may be exposed if the same memory is later reused in an observable path. ## 5. One-sentence report phrase A missing memory scrub in s390/zcrypt CCA clear key import could leave clear AES key material in reusable CPRB buffers, creating a local confidentiality risk if the same kernel memory is later exposed through buffer reuse. ## 6. Manual review recommendation MANUAL CHECK RECOMMENDED Cryptographic key material exposure is sensitive enough to justify manual review, even though the patch does not indicate memory corruption, privilege escalation, or network reachability. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: s390/zcrypt: Fix missing mem scrub at clear key import in cca_clr2cipherkey() [ Upstream Commit: 8e1c0def77b7450be0ed607ed0d7bae629d30020 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8e1c0def77b7450be0ed607ed0d7bae629d30020 Changed files: drivers/s390/crypto/zcrypt_ccamisc.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=8e1c0def77b7450be0ed607ed0d7bae629d30020 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-80708 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80708 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:L/UI:N/S:U/C:L/I:N/A:N The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N The Best / paranoid CVSS score: 4.7 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).