CVE-2026-46330 Revert "net/smc: Introduce TCP ULP support"
A use-after-free vulnerability in the Linux kernel's SMC TCP ULP support allows attackers to cause system instability or execute code.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-46330?
CVE-2026-46330 is a high-severity use after free vulnerability in Linux kernel, published on 9 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
Revert "net/smc: Introduce TCP ULP support"
This reverts commit d7cd421da9da2cc7b4d25b8537f66db5c8331c40.
As reported by Al Viro, the TCP ULP support for SMC is fundamentally broken. The implementation attempts to convert an active TCP socket into an SMC socket by modifying the underlying `struct file`, dentry, and inode in-place, which violates core VFS invariants that assume these structures are immutable for an open file, creating a risk of use after free errors and general system instability.
Given the severity of this design flaw and the fact that cleaner alternatives (e.g., LD_PRELOAD, BPF) exist for legacy application transparency, the correct course of action is to remove this feature entirely.
Weakness: CWE-416
Which versions are affected by CVE-2026-46330?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-46330?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-46330 being exploited?
There is no known exploitation of CVE-2026-46330 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-89696, BELL-CVE-2026-46330, DEBIAN-CVE-2026-46330, GHSA-fm5x-69c3-7mfj, ROOT-OS-DEBIAN-12-CVE-2026-46330, ROOT-OS-DEBIAN-13-CVE-2026-46330 and 2 more.