Linux kernel: unpatched ZDI bug reports with repro details leaked to public LKML (ksmbd RCE, CVSS 9.0)
Published Sources: pwn.watch
What is affected, what to do
On Oct 21, Trend Micro's Zero Day Initiative sent several unpatched Linux kernel vulnerability reports to security@kernel.org but Cc'd the public linux-kernel and subsystem lists, so full technical details (code paths, KASAN traces) are now public before fixes ship. The worst are two ksmbd (in-kernel SMB server) remote code execution bugs that ZDI scores CVSS 9.0: an SMB Direct integer underflow (needs an RDMA device and a writable share) and a protocol-dispatch race (needs a guest share).
The available sources name no fixed version. Check the vendor guidance in the references below.
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CVSS v3
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Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 30.00 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
On Oct 21, Trend Micro's Zero Day Initiative sent several unpatched Linux kernel vulnerability reports to security@kernel.org but Cc'd the public linux-kernel and subsystem lists, so full technical details (code paths, KASAN traces) are now public before fixes ship. The worst are two ksmbd (in-kernel SMB server) remote code execution bugs that ZDI scores CVSS 9.0: an SMB Direct integer underflow (needs an RDMA device and a writable share) and a protocol-dispatch race (needs a guest share). Also leaked: an skb_zerocopy local privilege escalation (ZDI-CAN-33367, CVSS 7.8), a vmwgfx out-of-bounds write LPE, and an nvmet info leak. ZDI-CAN-33367 now has a working public exploit: CloudLinux confirmed it gives any local user root on AlmaLinux 8, 9 and 10, Debian 12 and 13, and Ubuntu 24.04 and 26.04 where unprivileged user namespaces are allowed, and setting user.max_user_namespaces to 0 closes that path. No CVEs yet and no fixed mainline or stable release; the skb_zerocopy fix is posted for review but not merged, CloudLinux says fixed kernels for CloudLinux 9 and 10 (the AlmaLinux kernels 5.14.0-687.60.1.el9_8 and 6.12.0-211.69.1.el10_2) are in production and CloudLinux 7 hybrid and 8 kernels are in beta, KernelCare has a livepatch only for CloudLinux/AlmaLinux 10, the ksmbd race fix sits in the ksmbd maintainer tree, and an SMB Direct fix is in a branch aimed at Linux 7.5. No exploitation in the wild reported. Only machines running ksmbd are exposed to the RCEs.
Source: pwn.watch