Description
In the Linux kernel, the following vulnerability has been resolved: net/iucv: take a reference on the socket found in afiucv_hs_rcv() afiucv_hs_rcv() looks up the destination socket under iucv_sk_list.lock, drops the lock, and then passes the socket to the afiucv_hs_callback_*() handlers without holding a reference. AF_IUCV sockets are not RCU-protected and are freed synchronously by iucv_sock_kill() -> sock_put(), so a concurrent close can free the socket in the window between read_unlock() and the handler, which then dereferences freed memory (for example sk->sk_data_ready() in afiucv_hs_callback_syn()). Take a reference with sock_hold() while the socket is still on the list and release it with sock_put() once the handler has run.
References8
- git.kernel.org/stable/c/1801cb20a5025a787d6853e19c38db138344b4b4
- git.kernel.org/stable/c/4dc0e63abf8bc7ba8892e617c1fb8b204361e022
- git.kernel.org/stable/c/4fa349156043dc119721d067329714179f501749
- git.kernel.org/stable/c/5595ea59cdf29182cf6a270cacc1426c57b603de
- git.kernel.org/stable/c/5739be5c19495d709d902a2912c9102ce78740d5
- git.kernel.org/stable/c/bc6c6e546ffff8865daaeb622ef348c2d481e80f
- git.kernel.org/stable/c/c75a950e77356e526672cba4584080c6c8b793b6
- git.kernel.org/stable/c/e3e0679fc950191aff8f27fa78abcfc2462cff4a
Metrics
- CVSS 3.1
-
8.8
HIGH
Score source: CNA
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 0% percentile: 18 · as of 12 November 2026
- CWE
- CWE-416
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.