From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-74394][IMPORTANT] RDMA/srpt: fix integer overflow in immediate data length check [ Upstream Date: Sat, 15 Aug 2026 06:02:07 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-74394 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: 8 X-AL-KERNEL-ActionableScore-Lower: 7 X-AL-KERNEL-Commit: c82c860f8c8e4f4f454c9f14d0ad0c0466965f7d List-Id: CVE: CVE-2026-74394 Priority: IMPORTANT AL-KERNEL base severity: IMPORTANT KPANIC flag: NO Patch: RDMA/srpt: fix integer overflow in immediate data length check [ Upstream Commit: c82c860f8c8e4f4f454c9f14d0ad0c0466965f7d Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c82c860f8c8e4f4f454c9f14d0ad0c0466965f7d Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74394 Analysis date: Sat, 15 Aug 2026 06:02:07 -0400 ActionableScore: 8 ActionableScore lower bound: 7 Actionable bucket: Strong Important candidate / Actionable Moderate at minimum Manual review required: YES Summary: A network-adjacent integer overflow in RDMA srpt immediate-data length validation can let a malicious SRP initiator bypass request-size checks and pass a huge length to `sg_init_one()`, causing kernel crash and possible kernel memory exposure through later storage I/O handling. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-74394 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74394 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-2026-74394 IMPORTANT CHECK WITH IMPACT FROM ORIG NN IMPORTANT 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:L/A:H';CWE-190;CWE-125;*CWE-20;Other CVSS 'AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H';BEST CVSS score: '8.3';DESCR 'RDMA srpt accepts an immediate data length from the remote initiator and used it in an addition with imm_data_offset without overflow checking. A malicious initiator can make the computed request size wrap to a small value, bypass the request size check, and then cause a very large length to be passed to sg_init_one(). This can make the target treat memory beyond the received SRP command buffer as immediate data, which can crash the kernel and may expose kernel memory through later I/O handling. For the CVSS the PR:N is used because no local user account on the target is required beyond reachability to the RDMA SRP target and the ability to establish the protocol session. The attack vector is AV:A because SRP over RDMA is normally reachable only on an adjacent storage fabric or data center network rather than the public Internet. Impact is at least denial of service and the out-of-bounds read primitive makes confidentiality impact plausible, so this should not be treated as a low severity resource issue.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Strong Important candidate / Actionable Moderate at minimum (with actual score 8) YES OOB SIMPLEFIX NETWORK LINUS NO NO checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=8 ActionableScoreLower=7 ## 1. ActionableScore * Conservative score: 7 * Paranoid score: 8 * Final recommended bucket: **Strong Important candidate / Actionable Moderate at minimum**:: ## 2. Signal breakdown Triggered signals: * Remote reachable / network-triggerable: +2 The length field is controlled by a remote SRP initiator over RDMA/SRPT. This is not public Internet remote in the usual case, but it is network-triggerable from an RDMA storage fabric. * Memory corruption, weak/indirect corruption candidate: +1 The overflow lets a wrapped small `req_size` bypass validation and then passes an attacker-controlled huge length to `sg_init_one()`. This creates an invalid scatterlist length over memory beyond the received SRP command buffer. * Memory layout invariant restoration: +1 The patch restores consistency between `imm_data_offset`, `len`, and `req_size` before building the immediate-data scatterlist. * Reliable kernel crash / strong DoS: +1 A roughly 4GB scatterlist length from a small command buffer is a credible crash or severe target failure condition. * Confidentiality impact plausible: +1 The invalid scatterlist can make later I/O handling treat memory beyond the received command as data. This supports a plausible out-of-bounds read or kernel memory exposure concern. * Availability impact realistic: +1 The trigger is simple once the attacker can connect as a malicious SRP initiator, and the impact can be target-wide kernel crash or storage service failure. * Important filesystem/storage path: +1 SRPT is a storage target path. Corruption or disclosure in this path can affect storage I/O integrity and availability. * Rare AND difficult-to-reach subsystem/configuration: -1 SRPT over RDMA is usually deployed only in specialized storage or data-center fabrics, not on default general-purpose systems. Paranoid-only signal: * Integrity impact plausible: +1 If the oversized scatterlist is consumed as storage payload or affects target I/O state, limited integrity impact is defensible, although the patch does not show an arbitrary write primitive. ## 3. Reachability analysis A malicious SRP/RDMA initiator can trigger the bug by sending an immediate-data length such as `0xFFFFFFFF`, causing integer wraparound in the request-size calculation. No local account on the target is required if the attacker can reach and authenticate or otherwise connect to the SRPT target endpoint. This should be treated as adjacent-network reachable rather than broad Internet remote. RDMA/SRPT is normally limited to trusted storage networks, cluster fabrics, or data-center environments. Namespaces and containers are not the main privilege boundary here because the attacker is external to the target host and interacts through the storage protocol. The vulnerable path is not default-enabled on typical Linux systems. It matters on systems configured as RDMA SRP targets with immediate data support exposed to initiators. ## 4. Severity interpretation This is not an ordinary Moderate memory leak or local cleanup bug. The patch fixes a network-controlled integer overflow that directly affects scatterlist construction in a storage target. Realistically, the strongest demonstrated impact is kernel crash or SRPT target DoS. However, because the oversized scatterlist can reference memory beyond the received request buffer, confidentiality impact is plausible and manual review is warranted. Integrity impact is more speculative but defensible in the paranoid score because the corrupted scatterlist is part of storage I/O handling. Overall this behaves like a Strong Important candidate in affected RDMA storage deployments, and at minimum an Actionable Moderate that should not be auto-closed. ## 5. One-sentence report phrase A network-adjacent integer overflow in RDMA srpt immediate-data length validation can let a malicious SRP initiator bypass request-size checks and pass a huge length to `sg_init_one()`, causing kernel crash and possible kernel memory exposure through later storage I/O handling. ## 6. Manual review recommendation MANUAL CHECK REQUIRED Reason: this is a network-adjacent storage target bug with attacker-controlled length arithmetic feeding scatterlist construction. The likely impact is DoS, but the possible out-of-bounds memory exposure and storage I/O consequences require human review. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: RDMA/srpt: fix integer overflow in immediate data length check [ Upstream Commit: c82c860f8c8e4f4f454c9f14d0ad0c0466965f7d Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c82c860f8c8e4f4f454c9f14d0ad0c0466965f7d Changed files: drivers/infiniband/ulp/srpt/ib_srpt.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=c82c860f8c8e4f4f454c9f14d0ad0c0466965f7d ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-74394 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74394 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:N/S:U/C:H/I:N/A:H The Best / paranoid CVSS vector: AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H The Best / paranoid CVSS score: 8.3 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: 7 Paranoid ActionableScore: 8 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).