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Linux Kernel AF_IUCV Calls iucv_sock_kill on a NULL Pointer When Child Socket Allocation Fails, Crashing the Kernel on a Crafted Inbound Connection

Last refreshed2026-09-29

Status: NEW  |  Advisory ID: CVE-2026-68141

Key Details

CVECVE-2026-68141
CVSS Score / Version7.5 (High) / CVSS v3.1
Updated2026-08-19
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS Proseattack vector is network; attack complexity is low; privileges required is none; user interaction is none; scope is unchanged; confidentiality impact is none; integrity impact is none; availability impact is high.

What to Know

In the Linux kernel, the following vulnerability has been resolved:

net/af_iucv: fix NULL deref in afiucv_hs_callback_syn()

afiucv_hs_callback_syn() allocates the child socket with GFP_ATOMIC.

If the allocation fails, nsk is NULL.

The connection-refused path is entered when the listen state check

fails, the accept backlog is full, or nsk is NULL. The code

unconditionally calls iucv_sock_kill(nsk) in that path.

iucv_sock_kill() does not accept a NULL socket pointer and immediately

dereferences sk via sock_flag(sk, SOCK_ZAPPED). When nsk is NULL,

calling iucv_sock_kill(nsk) results in a NULL pointer dereference.

Only call iucv_sock_kill() when a child socket was successfully

allocated. (NVD)

References

SourceReference
NVDhttps://nvd.nist.gov/vuln/detail/CVE-2026-68141
CVEhttps://www.cve.org/CVERecord?id=CVE-2026-68141