# CVE-2026-98775: nitro_enclaves: fix use-after-free on SLOT_ALLOC failure

> A use-after-free in the Linux kernel nitro_enclaves driver allows local attackers to potentially execute code or escalate privileges via a specific ioctl failure path.

- **Severity:** Not scored
- **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 Oct 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-109094, BELL-CVE-2026-98775, DEBIAN-CVE-2026-98775, GHSA-8pj3-87fr-9h94, UBUNTU-CVE-2026-98775

## What is CVE-2026-98775?

CVE-2026-98775 is an use after free vulnerability in Linux, published on 18 Oct 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:

nitro_enclaves: fix use-after-free on SLOT_ALLOC failure

When ne_create_vm_ioctl() fails the SLOT_ALLOC request after
anon_inode_getfile() has succeeded, the error path calls
fput(enclave_file) and then frees ne_enclave.

In normal userspace context, fput() defers the final __fput() via
task_work. ne_enclave_release() therefore runs after ne_enclave has
already been freed and dereferences ne_enclave->slot_uid, causing a
use-after-free: KASAN: slab-use-after-free in ne_enclave_release.

The enclave has no slot allocated and is not yet linked into the
enclaves list on this error path, so ne_enclave_release() is expected
to return early when slot_uid is zero. However, reading slot_uid
already accesses the freed object.

Clear enclave_file->private_data before fput() on the error path.
ne_enclave_release() then returns immediately when private_data is
NULL, leaving the ioctl error path as the sole owner of ne_enclave.
This is safe because the file has not been fd_install()'d yet.

Tested on an AWS EC2 m5.2xlarge with CONFIG_KASAN=y. Without the
patch, the reproducer triggers a KASAN slab-use-after-free on every
SLOT_ALLOC failure. With the patch, no KASAN report is produced and
the SLOT_ALLOC error is still returned. Normal enclave creation and
teardown are unaffected.

## Which versions are affected by CVE-2026-98775?


## How do I fix CVE-2026-98775?

Apply the vendor's patch.

## Is CVE-2026-98775 being exploited?

There is no known exploitation of CVE-2026-98775 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98775 and fix it if it is affected.

What it is: CVE-2026-98775 is an use after free vulnerability in Linux, published on 18 Oct 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-2026-98775 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-2026-98775/ (Markdown: https://insights.sbomify.com/CVE-2026-98775/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98775
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98775
- OSV: https://osv.dev/vulnerability/CVE-2026-98775

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98775/
Summaries are generated and may contain mistakes; the official description above is the record.