# CVE-2026-23383: bpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing

> A race condition in the Linux kernel BPF JIT compiler on arm64 can cause torn reads of jump targets, potentially leading to arbitrary code execution or system crashes.

- **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:** 25 Mar 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-80619, BELL-CVE-2026-23383, DEBIAN-CVE-2026-23383, GHSA-887m-4qrh-hjq5, ROOT-OS-DEBIAN-12-CVE-2026-23383, ROOT-OS-DEBIAN-13-CVE-2026-23383, ROOT-OS-UBUNTU-2404-CVE-2026-23383, UBUNTU-CVE-2026-23383

## What is CVE-2026-23383?

CVE-2026-23383 is a high-severity vulnerability in Linux kernel, published on 25 Mar 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:

bpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing

struct bpf_plt contains a u64 target field. Currently, the BPF JIT
allocator requests an alignment of 4 bytes (sizeof(u32)) for the JIT
buffer.

Because the base address of the JIT buffer can be 4-byte aligned (e.g.,
ending in 0x4 or 0xc), the relative padding logic in build_plt() fails
to ensure that target lands on an 8-byte boundary.

This leads to two issues:
1. UBSAN reports misaligned-access warnings when dereferencing the
   structure.
2. More critically, target is updated concurrently via WRITE_ONCE() in
   bpf_arch_text_poke() while the JIT'd code executes ldr. On arm64,
   64-bit loads/stores are only guaranteed to be single-copy atomic if
   they are 64-bit aligned. A misaligned target risks a torn read,
   causing the JIT to jump to a corrupted address.

Fix this by increasing the allocation alignment requirement to 8 bytes
(sizeof(u64)) in bpf_jit_binary_pack_alloc(). This anchors the base of
the JIT buffer to an 8-byte boundary, allowing the relative padding math
in build_plt() to correctly align the target field.

## Which versions are affected by CVE-2026-23383?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-23383?

Apply the vendor's patch.

## Is CVE-2026-23383 being exploited?

There is no known exploitation of CVE-2026-23383 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-2026-23383 and fix it if it is affected.

What it is: CVE-2026-23383 is a high-severity vulnerability in Linux kernel, published on 25 Mar 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-2026-23383 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-2026-23383/ (Markdown: https://insights.sbomify.com/CVE-2026-23383/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23383
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23383
- OSV: https://osv.dev/vulnerability/CVE-2026-23383

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23383/
Summaries are generated and may contain mistakes; the official description above is the record.