# CVE-2026-63972: net: mana: Skip redundant detach on already-detached port

> A null pointer dereference in the Linux kernel's mana network driver can cause a system crash when a port is detached twice.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Jul 2026
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2026-63972, DEBIAN-CVE-2026-63972, GHSA-h62q-3pmg-9366, UBUNTU-CVE-2026-63972

## What is CVE-2026-63972?

CVE-2026-63972 is a high-severity vulnerability in Linux kernel, published on 19 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

net: mana: Skip redundant detach on already-detached port

When mana_per_port_queue_reset_work_handler() runs after a previous
detach succeeded but attach failed, the port is left in a detached
state with apc->tx_qp and apc->rxqs already freed. Calling
mana_detach() again unconditionally leads to NULL pointer dereferences
during queue teardown.

Add an early exit in mana_detach() when the port is already in
detached state (!netif_device_present) for non-close callers, making
it safe to call idempotently. This allows the queue reset handler and
other recovery paths to simply retry mana_attach() without redundant
teardown.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-63972?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-63972?

Apply the vendor's patch.

## Is CVE-2026-63972 being exploited?

There is no known exploitation of CVE-2026-63972 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-2026-63972 and fix it if it is affected.

What it is: CVE-2026-63972 is a high-severity vulnerability in Linux kernel, published on 19 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-63972 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-2026-63972/ (Markdown: https://insights.sbomify.com/CVE-2026-63972/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63972
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63972
- OSV: https://osv.dev/vulnerability/CVE-2026-63972

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63972/
Summaries are generated and may contain mistakes; the official description above is the record.