From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-99032][MODERATE 7.0] net/smc: protect clcsock lifetime in smc_getname Date: Mon, 26 Oct 2026 21:50:34 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-99032 X-AL-KERNEL-Priority: MODERATE 7.0 X-AL-KERNEL-Severity: MODERATE 7.0 X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: YES X-AL-KERNEL-ActionableScore: 5 X-AL-KERNEL-ActionableScore-Lower: unknown X-AL-KERNEL-Commit: e607017a553d2a48e428ec8b8ffb06bf3bb92ce9 List-Id: CVE: CVE-2026-99032 Priority: MODERATE 7.0 AL-KERNEL base severity: MODERATE KPANIC flag: YES Patch: net/smc: protect clcsock lifetime in smc_getname Commit: e607017a553d2a48e428ec8b8ffb06bf3bb92ce9 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e607017a553d2a48e428ec8b8ffb06bf3bb92ce9 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99032 Analysis date: Mon, 26 Oct 2026 21:50:34 -0400 ActionableScore: 5 ActionableScore lower bound: unknown Actionable bucket: Actionable Moderate / Strong Important candidate requiring manual review Manual review required: YES Summary: A local SMC socket race permits `smc_getname()` to dereference a released CLC socket and invoke an indirect operation through stale structured state. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-99032 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99032 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 7.0 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-2026-99032 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-99032 CHECK WITH IMPACT FROM ORIG NN MODERATE | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=4 LEGACY=MODERATE_KPANIC RESULT=SAME (final reconciliation agrees; DECISION: both MODERATE_KPANIC) 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:H/A:H';*CWE-416;CWE-362;**CWE-476;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7';DESCR 'A race in smc_getname allows smc clcsock to be released asynchronously after its pointer is loaded but before clcsock ops or the getname callback is accessed. This produces a confirmed slab use after free and may instead produce a NULL pointer dereference when the termination worker clears the pointer first. For the CVSS the PR:L value is selected because a local user or process must create or operate an SMC socket and invoke shutdown and getsockname. AC:H reflects the required timing window between the syscall and link group termination. The demonstrated impact is a local kernel crash. The paranoid score uses C:H I:H A:H because the stale socket is dereferenced and supplies an indirect ops callback target after free which creates a plausible but unproven privilege escalation path through controlled slab reuse. Automated impact decision path. The original SimpleNet classifier selected MODERATE. The primary LLM estimated paranoid CVSS 7 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 MODERATE to MODERATE_KPANIC because the CVSS score, vector or bug class threshold rule was applied. 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 has no review artifact for this run. Exact triggered rule markers were INCREASED_TO_HIGH_BASED_ON_GUESSCVSS and LOWERED_FROM_HIGH_BASED_ON_NULLPTR. The independent weaker Aegis shadow evaluated CVSS 2.5 and ActionableScore 4 with primitive class CLASS_B and manual review REQUIRED. Its independently reconciled impact was MODERATE_KPANIC. The shadow agreed with the final production impact and aggregation did not change that impact. The final reported impact is MODERATE_KPANIC.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate / Strong Important candidate requiring manual review (with actual score 5) MAYBE READ LOCK DANGER NULLPTR UAF IMPROVEONLY LINUS TEST KPANIC INCREASED_TO_HIGH_BASED_ON_GUESSCVSS KPANIC LOWERED_FROM_HIGH_BASED_ON_NULLPTR - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=5 PrimitiveClass=CLASS_B RealUAF=YES 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: 3. * Conservative score: 5. REAL UAF FLOOR 5 applied because a below-host-admin syscall reaches an active structured socket whose stale `ops->getname` callback is consumed. * Raw paranoid score: 3. * Paranoid score: 5. No additional speculative reclaim or C/I points. * Final recommended bucket: **Actionable Moderate / Strong Important candidate requiring manual review**:: 2. Signal breakdown * +2 Real UAF: `clcsock` can be released before `smc_getname()` dereferences it. * +1 Reliable kernel crash: KASAN confirms slab UAF; the alternate race produces a NULL dereference. * +1 Local unprivileged trigger: the supplied call path grounds socket operations through `getsockname()` and `shutdown()` without host-admin authority. * -1 Hard timing: demonstrated reproduction required test-only timing instrumentation between pointer load and asynchronous release. * Floor 5: stale structured state supplies `clcsock->ops` and an indirect callback invocation, giving material exploit surface beyond a fixed stale buffer. Not awarded: controlled reclaim, attacker-shaped replacement contents, arbitrary write, disclosure, integrity impact, or proven LPE. Structured-stale leverage is not separately scored because material reuse control is absent. The same crash receives no extra availability point. 3. Reachability analysis The assessed actor is a local non-root process operating its own SMC socket. No capability or namespace-scoped privilege check is shown, and host UID 0 is unnecessary. The process drives `shutdown()` and `getsockname()`, while asynchronous link-group termination performs the release. Specialized SMC infrastructure is relevant, but no rare-hardware penalty is justified by the supplied evidence. The race window appears difficult but can be retried with socket operations. 4. Primitive and severity reading This is a confirmed CLASS_B UAF of an active structured `struct socket`, not fixed stale storage. Release clears and frees `clcsock`; the concurrent syscall then reads its `ops` pointer and may invoke `getname`. That callback consumption creates material unknown leverage past the demonstrated crash, but no controlled callback target or reclaim is proven. ImportantCandidate is therefore YES for Important-versus-Moderate review, while CLASS_A and high-impact C/I claims are unsupported. Auto-downgrade is unsafe because a below-host-admin active-object UAF reaches an indirect operation. 5. One-sentence report phrase A local SMC socket race permits `smc_getname()` to dereference a released CLC socket and invoke an indirect operation through stale structured state. 6. Manual review advice MANUAL CHECK REQUIRED Review reclaim behavior and whether repeated socket allocation can influence the stale socket’s `ops` callback target. 7. Call-site confidence Call-site confidence: high ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: net/smc: protect clcsock lifetime in smc_getname Commit: e607017a553d2a48e428ec8b8ffb06bf3bb92ce9 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e607017a553d2a48e428ec8b8ffb06bf3bb92ce9 Commit description: smc_getname() dereferences smc->clcsock without holding clcsock_release_lock. Link-group termination can release the CLC socket through smc_close_active_abort() while the SMC socket is still open, for example after shutdown(SHUT_WR). A getsockname() caller can load smc->clcsock, then the termination worker can clear the pointer and call sock_release() before the caller accesses clcsock->ops or invokes getname(). This causes a use-after-free; if the worker clears the pointer before the load, it causes a NULL dereference. The syscall's file reference keeps the SMC socket alive but does not prevent asynchronous release of its CLC socket. KASAN reported the following with test-only timing instrumentation: BUG: KASAN: slab-use-after-free in smc_getname+0x19e/0x1b0 Read of size 8 at addr ffff888109abb4e0 by task poc/103 Call Trace: smc_getname+0x19e/0x1b0 do_getsockname+0xe5/0x170 __sys_getsockname+0x8c/0x100 Allocated by task 95: sock_alloc_inode+0x1e/0x280 sock_alloc+0x3d/0x240 __sock_create+0x7e/0x430 smc_create+0x121/0x240 Freed by task 0: kmem_cache_free+0xcc/0x340 rcu_core+0x50a/0x1850 Last potentially related work creation: evict+0x446/0x6c0 smc_clcsock_release+0xa8/0xd0 smc_close_active_abort+0x26a/0x3a0 __smc_lgr_terminate.part.0+0x137/0x2e0 Hold clcsock_release_lock across the pointer check and the getname() callback to serialize with smc_clcsock_release(). Return -EBADF if the CLC socket has already been released, preserving the existing peer state check and the callback's return value otherwise. Fixes: b03faa1 ("net/smc: postpone release of clcsock") Cc: stable@vger.kernel.org Signed-off-by: Chengfeng Ye Reviewed-by: Mahanta Jambigi Reviewed-by: Dust Li Link: https://patch.msgid.link/20261008084444.787449-1-nicoyip.dev@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman Changed files: net/smc/af_smc.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=e607017a553d2a48e428ec8b8ffb06bf3bb92ce9 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-99032 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-99032 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:N/I:N/A:H The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H The Best / paranoid CVSS score: 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: 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: MODERATE KPANIC detected for this report: YES Published priority for this report (same as in Subject): MODERATE 7.0 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).