# CVE-2026-90057: slip: remove slip_hangup() to fix use-after-free in slip_receive_buf()

> A race condition in the Linux kernel's SLIP driver allows a use-after-free, potentially leading to code execution or system crash.

- **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:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-102930, BELL-CVE-2026-90057, DEBIAN-CVE-2026-90057, GHSA-45fm-hw2m-668x, UBUNTU-CVE-2026-90057

## What is CVE-2026-90057?

CVE-2026-90057 is a high-severity use after free vulnerability in Linux, published on 17 Sep 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:

slip: remove slip_hangup() to fix use-after-free in slip_receive_buf()

Jaeyoung Chung and Eulgyu Kim reported a slab-use-after-free read
in slip_receive_buf() when racing against tty hangup.

tty_ldisc_hangup() calls ld->ops->hangup() while holding only
a read lock on tty->ldisc_sem (via tty_ldisc_ref()).
Because slip_hangup() simply called slip_close(), it ran concurrently
with reader functions such as slip_receive_buf().

slip_close() unregisters and frees the net device and its private
struct slip, causing concurrent reader threads in slip_receive_buf()
to dereference freed memory.

Line discipline close() is already guaranteed to be called under
the write lock of tty->ldisc_sem during hangup processing
(in tty_ldisc_reinit() or tty_ldisc_kill()).

Remove slip_hangup() so teardown is serialized cleanly by slip_close().

## Which versions are affected by CVE-2026-90057?


## How do I fix CVE-2026-90057?

Apply the vendor's patch.

## Is CVE-2026-90057 being exploited?

There is no known exploitation of CVE-2026-90057 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90057 and fix it if it is affected.

What it is: CVE-2026-90057 is a high-severity use after free vulnerability in Linux, published on 17 Sep 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-2026-90057 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-2026-90057/ (Markdown: https://insights.sbomify.com/CVE-2026-90057/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90057
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90057
- OSV: https://osv.dev/vulnerability/CVE-2026-90057

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90057/
Summaries are generated and may contain mistakes; the official description above is the record.