CVE-2025-21863 io_uring: prevent opcode speculation
Attackers can exploit speculative execution flaws in the Linux kernel's io_uring subsystem to potentially read sensitive memory contents.
- 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-2025-21863?
CVE-2025-21863 is a high-severity vulnerability in Linux kernel, published on 12 Mar 2025. 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:
io_uring: prevent opcode speculation
sqe->opcode is used for different tables, make sure we santitise it against speculations.
Which versions are affected by CVE-2025-21863?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-21863?
Apply the vendor's patch.
Is CVE-2025-21863 being exploited?
There is no known exploitation of CVE-2025-21863 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-58547, AZL-58563, BELL-CVE-2025-21863, DEBIAN-CVE-2025-21863, GHSA-qj2f-x8m5-rrr3, ROOT-OS-DEBIAN-11-CVE-2025-21863 and 4 more.