CVE-2026-89906 LoongArch: BPF: Refactor jump offset calculation in tail call
Incorrect jump offset calculation in the LoongArch BPF JIT compiler can cause soft lockups, leading to a denial of service.
- 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-2026-89906?
CVE-2026-89906 is a high-severity denial of service vulnerability in Linux, published on 16 Sep 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:
LoongArch: BPF: Refactor jump offset calculation in tail call
The old macro-based jmp_offset calculation derives the jump distance from a stale prior-pass code stride, which can lead to wrong branch offsets and soft lockups under extra JIT passes.
Fix this by calculating the offset directly on the absolute target: "ctx->offset[insn + 1] - ctx->idx".
To avoid a false 16-bit range check abort during size estimation, add a "ctx->image == NULL" guard to inject a safe dummy offset.
Which versions are affected by CVE-2026-89906?
How do I fix CVE-2026-89906?
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-2026-89906 being exploited?
There is no known exploitation of CVE-2026-89906 in the wild and no public exploit code.
Sources
Also known as AZL-101568, BELL-CVE-2026-89906, DEBIAN-CVE-2026-89906, GHSA-gpr4-rp6h-2879, UBUNTU-CVE-2026-89906.