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

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().

Affected packages & fixed versions

Affected products (as reported)

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