In the Linux kernel, the following vulnerability has been resolved:
net/rose: fix NULL pointer dereference in rosetransmitlink on reconnect
syzkaller reported a bug [1], and the reproducer is available at [2].
ROSE sockets use four sk->skstate values: TCPCLOSE, TCPLISTEN, TCPSYNSENT, and TCPESTABLISHED. roseconnect() already rejects calls for TCPESTABLISHED (-EISCONN) and TCPCLOSE with SSCONNECTING (-ECONNREFUSED), but lacks a check for TCPSYNSENT.
When roseconnect() is called a second time while the first connection attempt is still in progress (TCPSYNSENT), it overwrites rose->neighbour via rosegetneigh(). If that returns NULL, the socket is left with rose->state == ROSESTATE1 but rose->neighbour == NULL. When the socket is subsequently closed, roserelease() sees ROSESTATE1 and calls rosewriteinternal() -> rosetransmitlink(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 TCPSYNSENT to complete the state validation in rose_connect().
[1] https://syzkaller.appspot.com/bug?extid=d00f90e0af54102fb271 [2] https://gist.github.com/mrpre/9e6779e0d13e2c66779b1653fef80516
{
"cna_assigner": "Linux",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23460.json"
}