Cybersecurity
Linux KSMBD flaws lack kernel fixes
Two KSMBD remote code execution flaws were described as affecting Linux servers, with one reachable before authentication and the other tied to SMB Direct, while fixes had not yet landed in mainline.
- Trend Micro's Zero Day Initiative said two KSMBD flaws had been publicly reported and rated 9.0.
- One flaw could be reached before network authentication, while the other needed SMB Direct and an RDMA-capable interface.
- As of Thursday, the article said neither issue had a named fix in mainline kernel code or linux-next.
- The ZDI reports credited TrendAI as the finder, and the kernel security guidance said AI-discovered bugs should be sent to subsystem mailing lists.
The article said the two flaws affected KSMBD, the Linux kernel's SMB server. It described one issue as an integer underflow in the SMB Direct path and the other as a race in handler selection. One flaw was said to work without authentication, while the other needed a writable share, an RDMA-capable interface and a client using SMB Direct. The article said that, as of Thursday, neither flaw had a named fix in the mainline kernel or in linux-next. Phoronix said Stefan Metzmacher had submitted a fix for the SMB Direct issue for the next development cycle, but the article said that claim had not been confirmed elsewhere. It also said the kernel project only assigns CVE identifiers after a stable-tree fix exists. The ZDI reports credited TrendAI, Trend Micro's AI scanner, as the finder. The article said the Linux kernel's security documentation, updated in May 2026 after guidance from Linus Torvalds, treated AI-found bugs as already public and directed them to subsystem mailing lists.
Named in this story
People
- Stefan Metzmacher
- was said to have submitted a fix for ZDI-CAN-33549
- Linus Torvalds
- his guidance informed the kernel security documentation update
- Greg Kroah-Hartman
- replied quickly to several of the kernel reports
- p1r0x
- was named as the discoverer of ZDI-CAN-33367
Companies
- Trend Micro
- the company behind Zero Day Initiative and TrendAI
- VMware
- was named in an unrelated virtual GPU driver report
Organisations
- Zero Day Initiative
- rated the flaws 9.0 and published the reports
Products and systems
- KSMBD
- the Linux kernel SMB server affected by the two flaws
- TrendAI
- the AI scanner credited as the finder in the ZDI reports
- Linux kernel
- its mainline and linux-next trees had no named fixes as of Thursday
- linux-next
- the integration tree that had not yet taken the fixes
- Red Hat Enterprise Linux
- was said not to include KSMBD by default
- ConnMan
- was named in a separate buffer overflow report
How the source tells it
The source was a plain technical security report with no distinct emotive framing.
No emotive framing was found in the original.