# CVE-2025-37893: LoongArch: BPF: Fix off-by-one error in build_prologue()

> A local attacker can cause a kernel hard lockup on LoongArch systems by executing BPF programs with tailcalls due to an off-by-one error in the JIT compiler.

- **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:** 18 Apr 2025
- **Updated:** 5 Aug 2026
- **Also known as:** AZL-61445, BELL-CVE-2025-37893, DEBIAN-CVE-2025-37893, GHSA-3xjw-75cj-9fvw, ROOT-OS-DEBIAN-12-CVE-2025-37893, UBUNTU-CVE-2025-37893

## What is CVE-2025-37893?

CVE-2025-37893 is a high-severity denial of service vulnerability in Linux kernel, published on 18 Apr 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:

LoongArch: BPF: Fix off-by-one error in build_prologue()

Vincent reported that running BPF progs with tailcalls on LoongArch
causes kernel hard lockup. Debugging the issues shows that the JITed
image missing a jirl instruction at the end of the epilogue.

There are two passes in JIT compiling, the first pass set the flags and
the second pass generates JIT code based on those flags. With BPF progs
mixing bpf2bpf and tailcalls, build_prologue() generates N insns in the
first pass and then generates N+1 insns in the second pass. This makes
epilogue_offset off by one and we will jump to some unexpected insn and
cause lockup. Fix this by inserting a nop insn.

Weakness: CWE-193 (Off-by-one Error)

## Which versions are affected by CVE-2025-37893?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-37893?

Apply the vendor's patch.

## Is CVE-2025-37893 being exploited?

There is no known exploitation of CVE-2025-37893 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-37893 and fix it if it is affected.

What it is: CVE-2025-37893 is a high-severity denial of service vulnerability in Linux kernel, published on 18 Apr 2025. 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-2025-37893 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2025-37893/ (Markdown: https://insights.sbomify.com/CVE-2025-37893/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-37893
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-37893
- OSV: https://osv.dev/vulnerability/CVE-2025-37893

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-37893/
Summaries are generated and may contain mistakes; the official description above is the record.