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

Summary

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().

Timeline

1. Sep 17, 2026, 4:05 PM UTCCVE published
2. Oct 19, 2026, 8:57 AM UTCRecord last updated

Affected versions

• Linux 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 Linux

  2.6.32

• KernelLinux

  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

References 6