From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2022-49803][LOW] netdevsim: Fix memory leak of nsim_dev->fa_cookie [ Upstream Date: Mon, 12 Oct 2026 20:51:41 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2022-49803 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: 207edad5717e0a5709ce8467f0eff41c607835c9 List-Id: CVE: CVE-2022-49803 Priority: LOW AL-KERNEL base severity: LOW KPANIC flag: NO Patch: netdevsim: Fix memory leak of nsim_dev->fa_cookie [ Upstream Commit: 207edad5717e0a5709ce8467f0eff41c607835c9 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=207edad5717e0a5709ce8467f0eff41c607835c9 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2022-49803 Analysis date: Mon, 12 Oct 2026 20:51:41 -0400 ActionableScore: 0 ActionableScore lower bound: unknown Actionable bucket: Ordinary Moderate Manual review required: NO Summary: A privileged netdevsim teardown path leaked the allocated fa_cookie, but the demonstrated effect is limited to a small persistent kernel memory leak without UAF, corruption, remote reachability, or established host-wide exhaustion. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2022-49803 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2022-49803 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-2022-49803 LOW https://www.kernelcve.org/list/?q=CVE-2022-49803 CHECK WITH IMPACT FROM ORIG NN IMPORTANT | AEGIS IMPACT LOW AEGIS_AS=0 LEGACY=LOW RESULT=SAME (legacy and Aegis reconciliation agree; DECISION: both LOW) Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L';*CWE-401;*CWE-772;BEST CVSS score: '2.3';DESCR 'netdevsim retains the allocated fa_cookie after a simulated device is removed because the teardown path does not release this allocation. The demonstrated primitive is a persistent kernel memory leak of a small object, with no UAF, invalid dereference, out of bounds access, information disclosure, or write primitive. Repeated privileged device creation and removal could accumulate leaked memory, but the supplied evidence does not show that a small number of operations can cause host wide exhaustion. For the CVSS the PR:H reflects that configuring and removing netdevsim devices normally requires administrative control of the relevant device management interfaces. The issue is local and is not reachable through ordinary network traffic. Confidentiality and integrity are not affected. Availability impact is rated Low because practical system wide exhaustion is not established.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 0) MAYBE WRITE OOB LEAK NETWORK CVEOUTDATED LOWERED_FROM_HIGH_BASED_ON_GUESSCVSS DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 KPANIC_UNSUPPORTED_REMOVED - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=0 PrimitiveClass=NONE RealUAF=NO HostAdminRequired=YES NamespaceScopedPrivilege=NO ImportantCandidate=NO ManualReview=NO AutoDowngradeAllowed=YES RequiresHostUID0=UNKNOWN AuthorizationDecisionBypass=NO ProtectedResourceImpact=NONE B4PendingReview=NO B4PendingConfirmed=NO ## 1. ActionableScore * Raw conservative score: -1 * Conservative score: 0 * Raw paranoid score: -1 * Paranoid score: 0 * Applied lower score boundary: -1 -> 0 * No UAF floor, Important-preservation rule, or upper cap applies. * Final recommended bucket: **Ordinary Moderate**:: ## 2. Signal breakdown Positive signals: * +1 Concrete persistent kernel resource leak. `nsim_dev_trap_fa_cookie_write()` allocates `fa_cookie`, but the original removal path permanently loses that allocation. * No generic resource-exhaustion point was added. The demonstrated object is eight bytes, and realistic host-wide accumulation is not established. Negative signals: * -2 Full host-admin-equivalent privilege. The complete sequence uses privileged netdevsim configuration and removal interfaces rather than an ordinary networking data path. Signals not awarded: * No UAF, double release, stale dereference, OOB access, or memory overwrite. * No reliable crash or strong DoS is demonstrated. * No confidentiality, integrity, authorization, or protected-resource impact. * No remote or ordinary local unprivileged trigger is established. * No additional exhaustion point because repeatable host-wide pressure is unsupported. * NEW52 B5-R does not apply because there is no OOB write, retry-accumulated index, or later consumption of corrupted state. * NEW53 B3-PENDING does not apply because no shared-backing write exists. * NEW54 B4-PENDING does not apply because no authorization decision is changed from DENY to ALLOW. ## 3. Reachability analysis The demonstrated path requires writing the netdevsim fault-action cookie and subsequently removing the simulated device. These are host device-management operations exposed through privileged debugfs or sysfs-style control interfaces, not packet-triggered operations. The complete trigger is not shown to work using an attacker-created user or network namespace. Netdevsim bus creation and destruction are host-global management operations, so `NamespaceScopedPrivilege=NO`. The exact requirement for numeric host UID 0 rather than an equivalent privileged management context is not shown, so `RequiresHostUID0=UNKNOWN`. The system must have netdevsim available and the relevant management interface exposed. No physical hardware is required. There is no race. Repeated privileged create, write, and remove cycles could accumulate allocations, but each demonstrated leak is very small and practical memory exhaustion is not established. ## 4. Primitive and severity interpretation The exact primitive is a persistent allocation leak: an allocated `fa_cookie` remains unfreed when `nsim_dev` is removed. The pointer is not used after its lifetime ends, and no freed storage is accessed or modified. This is neither active structured-object corruption nor fixed stale storage. It is a missing cleanup operation with no demonstrated post-lifetime access. There is no repeated release or refcount mutation. `PrimitiveClass=NONE` is appropriate because the evidence establishes only resource retention, not a corruption, ownership, authorization, or security-boundary primitive. The practical consequence is a small privileged kernel memory leak. Host-wide DoS remains theoretical and poorly supported. `ImportantCandidate=NO` because there is no Important-preserving primitive or meaningful unresolved exploitation leverage. `AutoDowngradeAllowed=YES` because automatic low-priority handling would not discard a UAF, write primitive, authorization bypass, or cross-boundary effect. ## 5. One-sentence report phrase A privileged netdevsim teardown path leaked the allocated fa_cookie, but the demonstrated effect is limited to a small persistent kernel memory leak without UAF, corruption, remote reachability, or established host-wide exhaustion. ## 6. Manual review recommendation NO MANUAL CHECK NEEDED The one-line cleanup fix addresses a concrete but small privileged resource leak, with no evidence of memory corruption, authorization bypass, crash, or realistic strong availability impact. ## 7. Call-site confidence Call-site confidence: high ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: netdevsim: Fix memory leak of nsim_dev->fa_cookie [ Upstream Commit: 207edad5717e0a5709ce8467f0eff41c607835c9 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=207edad5717e0a5709ce8467f0eff41c607835c9 Changed files: drivers/net/netdevsim/dev.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=207edad5717e0a5709ce8467f0eff41c607835c9 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2022-49803 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2022-49803 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: Not available The Best / paranoid CVSS vector: AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L The Best / paranoid CVSS score: 2.3 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).