Linux Kernel: ROSE socket NULL ptr deref in rose_transmit_link on reconnect
CVE-2026-23460 Published on April 3, 2026
net/rose: fix NULL pointer dereference in rose_transmit_link on reconnect
In the Linux kernel, the following vulnerability has been resolved:
net/rose: fix NULL pointer dereference in rose_transmit_link on reconnect
syzkaller reported a bug [1], and the reproducer is available at [2].
ROSE sockets use four sk->sk_state values: TCP_CLOSE, TCP_LISTEN,
TCP_SYN_SENT, and TCP_ESTABLISHED. rose_connect() already rejects
calls for TCP_ESTABLISHED (-EISCONN) and TCP_CLOSE with SS_CONNECTING
(-ECONNREFUSED), but lacks a check for TCP_SYN_SENT.
When rose_connect() is called a second time while the first connection
attempt is still in progress (TCP_SYN_SENT), it overwrites
rose->neighbour via rose_get_neigh(). If that returns NULL, the socket
is left with rose->state == ROSE_STATE_1 but rose->neighbour == NULL.
When the socket is subsequently closed, rose_release() sees
ROSE_STATE_1 and calls rose_write_internal() ->
rose_transmit_link(skb, NULL), causing a NULL pointer dereference.
Per connect(2), a second connect() while a connection is already in
progress should return -EALREADY. Add this missing check for
TCP_SYN_SENT to complete the state validation in rose_connect().
[1] https://syzkaller.appspot.com/bug?extid=d00f90e0af54102fb271
[2] https://gist.github.com/mrpre/9e6779e0d13e2c66779b1653fef80516
Products Associated with CVE-2026-23460
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Affected Versions
Linux:- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below c2ab74c12932e52cfa1e7e4582d42b0c8bec96c7 is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below 0c9fb70a206a8734e10468ecc24d57c7596cf64e is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below 508f49ccbe0329641bb681f7d0052bb4e5943252 is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below 0c3e8bff808f17ad37a51d8e719eed22c7863120 is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below a12254050e3050f1011cd24f3b880a6882d0139d is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below e1f0a18c9564cdb16523c802e2c6fe5874e3d944 is affected.
- Version 2.6.12 is affected.
- Before 2.6.12 is unaffected.
- Version 6.1.167, <= 6.1.* is unaffected.
- Version 6.6.130, <= 6.6.* is unaffected.
- Version 6.12.78, <= 6.12.* is unaffected.
- Version 6.18.20, <= 6.18.* is unaffected.
- Version 6.19.10, <= 6.19.* is unaffected.
- Version 7.0-rc5, <= * is unaffected.