CVE-2026-23217 riscv: trace: fix snapshot deadlock with sbi ecall
A local attacker with tracing privileges can cause a kernel deadlock on RISC-V systems by enabling function tracing on SBI ecall functions.
- 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-2026-23217?
CVE-2026-23217 is a medium-severity denial of service vulnerability in Linux kernel, published on 18 Feb 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:
riscv: trace: fix snapshot deadlock with sbi ecall
If sbi_ecall.c's functions are traceable,
echo "__sbi_ecall:snapshot" > /sys/kernel/tracing/set_ftrace_filter
may get the kernel into a deadlock.
(Functions in sbi_ecall.c are excluded from tracing if CONFIG_RISCV_ALTERNATIVE_EARLY is set.)
__sbi_ecall triggers a snapshot of the ringbuffer. The snapshot code raises an IPI interrupt, which results in another call to __sbi_ecall and another snapshot...
All it takes to get into this endless loop is one initial __sbi_ecall. On RISC-V systems without SSTC extension, the clock events in timer-riscv.c issue periodic sbi ecalls, making the problem easy to trigger.
Always exclude the sbi_ecall.c functions from tracing to fix the potential deadlock.
sbi ecalls can easiliy be logged via trace events, excluding ecall functions from function tracing is not a big limitation.
Weakness: CWE-667
Which versions are affected by CVE-2026-23217?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-23217?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-23217 being exploited?
There is no known exploitation of CVE-2026-23217 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-23217, DEBIAN-CVE-2026-23217, GHSA-787p-86v4-hhfg, ROOT-OS-DEBIAN-13-CVE-2026-23217, ROOT-OS-UBUNTU-2204-CVE-2026-23217, ROOT-OS-UBUNTU-2404-CVE-2026-23217 and 1 more.