# 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.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** Yes
- **Published:** 16 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-101568, BELL-CVE-2026-89906, DEBIAN-CVE-2026-89906, GHSA-gpr4-rp6h-2879, UBUNTU-CVE-2026-89906

## 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.

## Is CVE-2026-89906 being exploited?

There is no known exploitation of CVE-2026-89906 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89906 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-89906 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-89906/ (Markdown: https://insights.sbomify.com/CVE-2026-89906/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89906
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89906
- OSV: https://osv.dev/vulnerability/CVE-2026-89906

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89906/
Summaries are generated and may contain mistakes; the official description above is the record.