CVE-2026-23460

MediumCVSS 5.5

Published: 03/04/2026(UTC)Updated: 24/07/2026(UTC)Translated: 25/07/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

Low risk

0.12%

2th percentile - higher than 2% of all known CVEs

Summary

In the Linux kernel, in the ROSE protocol, there is a NULL pointer dereference in rose_transmit_link on reconnect. When rose_connect() is called a second time while the first connection is in progress (TCP_SYN_SENT), it overwrites rose->neighbour, and if rose_get_neigh() returns NULL, the socket is left with rose->neighbour == NULL. Closing the socket leads to a NULL pointer dereference. A check for TCP_SYN_SENT is missing.

Risk Assessment

NULL pointer dereference can cause a kernel panic when attempting to reconnect via the ROSE protocol, leading to denial of service.

Recommendation

Apply the Linux kernel patch that adds a check for TCP_SYN_SENT in rose_connect() and returns -EALREADY. Update the kernel to a version containing the fix.

Original NVD description (English source)

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