What’s Vulnerable › Vulnerabilities

CVE-2026-64004: net/iucv: fix locking in .getsockopt

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-19 · updated 2026-10-19
• Weakness: CWE-667

Description

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.

Affected products

• Linux kernel: from 3.4 before 5.10.259; from 5.11 before 5.15.210; from 5.16 before 6.1.176; from 6.2 before 6.6.143; from 6.7 before 6.12.93; from 6.13 before 6.18.35 — fixed in 5.10.259, 5.15.210, 6.1.176, 6.12.93, 6.18.35, 6.6.143

How to fix

Upgrade to a fixed version: Linux kernel 5.10.259, 5.15.210, 6.1.176, 6.12.93. Check the vendor advisory for mitigations.

References

• 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

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