net/iucv: fix locking in .getsockopt
In the Linux kernel, the following vulnerability has been resolved: net/iucv: fix locking in .getsockopt Mirror iucv_sock_setsockopt() and wrap the whole switch in lock_sock()/release_sock(). The pre-existing SO_MSGLIMIT-only lock becomes redundant and is removed. Any AF_IUCV HIPER user can potentially crash the kernel by racing recvmsg() with getsockopt(SO_MSGSIZE): the SO_MSGSIZE arm dereferences iucv->hs_dev->mtu after iucv_sock_close() (called from the racing recvmsg()) has set hs_dev to NULL, producing a NULL pointer dereference oops.
02 / AFFECTED SOFTWARE
Affected packages
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: net/iucv: fix locking in .getsockopt Mirror iucv_sock_setsockopt() and wrap the whole switch in lock_sock()/release_sock(). The pre-existing SO_MSGLIMIT-only lock becomes redundant and is removed. Any AF_IUCV HIPER user can potentially crash the kernel by racing recvmsg() with getsockopt(SO_MSGSIZE): the SO_MSGSIZE arm dereferences iucv->hs_dev->mtu after iucv_sock_close() (called from the racing recvmsg()) has set hs_dev to NULL, producing a NULL pointer dereference oops.
05 / REFERENCES
Further evidence
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- https://git.kernel.org/stable/c/1fc30bd4e55e2dd622d2d366cecd732c1841bbee
- https://git.kernel.org/stable/c/3589d20a666caf30ad100c960a2de7de390fce88
- https://git.kernel.org/stable/c/45bb8de8c95d8899f4b8f61bd9bceb8132af73cb
- https://git.kernel.org/stable/c/69554adc7a6fa04ede3ad7512321d83748e3c920
- https://git.kernel.org/stable/c/6e792b8dd3002bbc4136745928a9605df1a72b8a
- https://git.kernel.org/stable/c/884eb247b74d86db97e3a37f0d6fc8e1e83590dd
- https://git.kernel.org/stable/c/9817369243380e287ebe5525411557eaa3aa2a79
- https://git.kernel.org/stable/c/cd691beafea0dd779e69e81ccc26b0ab50efcb5e
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64004.json
- https://nvd.nist.gov/vuln/detail/CVE-2026-64004