# CVE-2023-53272: net: ena: fix shift-out-of-bounds in exponential backoff

> A shift-out-of-bounds error in the Linux kernel ENA network driver can cause a system crash during device reset operations.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/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 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2023-53272, DEBIAN-CVE-2023-53272, GHSA-7cp5-c68m-6w8h, UBUNTU-CVE-2023-53272

## What is CVE-2023-53272?

CVE-2023-53272 is a high-severity vulnerability in Linux kernel, published on 16 Sep 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:

net: ena: fix shift-out-of-bounds in exponential backoff

The ENA adapters on our instances occasionally reset.  Once recently
logged a UBSAN failure to console in the process:

  UBSAN: shift-out-of-bounds in build/linux/drivers/net/ethernet/amazon/ena/ena_com.c:540:13
  shift exponent 32 is too large for 32-bit type 'unsigned int'
  CPU: 28 PID: 70012 Comm: kworker/u72:2 Kdump: loaded not tainted 5.15.117
  Hardware name: Amazon EC2 c5d.9xlarge/, BIOS 1.0 10/16/2017
  Workqueue: ena ena_fw_reset_device [ena]
  Call Trace:
  <TASK>
  dump_stack_lvl+0x4a/0x63
  dump_stack+0x10/0x16
  ubsan_epilogue+0x9/0x36
  __ubsan_handle_shift_out_of_bounds.cold+0x61/0x10e
  ? __const_udelay+0x43/0x50
  ena_delay_exponential_backoff_us.cold+0x16/0x1e [ena]
  wait_for_reset_state+0x54/0xa0 [ena]
  ena_com_dev_reset+0xc8/0x110 [ena]
  ena_down+0x3fe/0x480 [ena]
  ena_destroy_device+0xeb/0xf0 [ena]
  ena_fw_reset_device+0x30/0x50 [ena]
  process_one_work+0x22b/0x3d0
  worker_thread+0x4d/0x3f0
  ? process_one_work+0x3d0/0x3d0
  kthread+0x12a/0x150
  ? set_kthread_struct+0x50/0x50
  ret_from_fork+0x22/0x30
  </TASK>

Apparently, the reset delays are getting so large they can trigger a
UBSAN panic.

Looking at the code, the current timeout is capped at 5000us.  Using a
base value of 100us, the current code will overflow after (1<<29).  Even
at values before 32, this function wraps around, perhaps
unintentionally.

Cap the value of the exponent used for this backoff at (1<<16) which is
larger than currently necessary, but large enough to support bigger
values in the future.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2023-53272?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2023-53272?

Apply the vendor's patch.

## Is CVE-2023-53272 being exploited?

There is no known exploitation of CVE-2023-53272 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-2023-53272 and fix it if it is affected.

What it is: CVE-2023-53272 is a high-severity vulnerability in Linux kernel, published on 16 Sep 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-2023-53272 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-2023-53272/ (Markdown: https://insights.sbomify.com/CVE-2023-53272/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-53272
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-53272
- OSV: https://osv.dev/vulnerability/CVE-2023-53272

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-53272/
Summaries are generated and may contain mistakes; the official description above is the record.