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CVE-2026-74467
s390/qeth: Check CAP_NET_ADMIN for private ioctls
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem drivers/s390. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-74467 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | fixedDLA-4777-1 · 2026-09-08 · text | 6.1.187-1 | Update the kernel and reboot. DLA-4777-1 shipped the fix on 2026-09-08, in 6.1.187-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixedDSA-6466-1 · 2026-08-25 · text | 6.12.105-1 | Update the kernel and reboot. DSA-6466-1 shipped the fix on 2026-08-25, in 6.12.105-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.8-1 | Update the kernel and reboot. Fixed in 7.1.8-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.8-1 | Update the kernel and reboot. Fixed in 7.1.8-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4788-1 · 2026-09-19 · text | 6.12.107-1~deb12u1 | Update the kernel and reboot. DLA-4788-1 shipped the fix on 2026-09-19, in 6.12.107-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
Gate the SIOCDEVPRIVATE ioctl commands SIOC_QETH_ADP_SET_SNMP_CONTROL, SIOC_QETH_GET_CARD_TYPE and SIOC_QETH_QUERY_OAT with CAP_NET_ADMIN capable check to ensure unprivileged users cannot invoke them.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
drivers/s390/net/qeth_core_main.c
- What this is
- NETWORKING DRIVERSMAINTAINERS section matched on drivers/s390/net/ · netdev@vger.kernel.org · Maintained
- Kernel module
- qeth
Check it on the machine
grep -wE 'CONFIG_QETH|CONFIG_S390' /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
lsmod | grep -w qethPrints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.
Show whether Debian builds this, per release
Debian does not build this code in 2 releases. It does build it in 3 releases, so the answer depends on which release the machine runs.
- bookwormn
- trixieMnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt/amd64, arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt/arm64, armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64
- forky, sidMnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt-amd64, arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt-arm64, armhf/armmp, armhf/armmp-lpae, loong64/loong64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64
- bookworm · linux-6.12n
- n
- not enabled on any flavour - this release does not build the code
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_QETH, CONFIG_S390
- Reads as
- all on means the file is compiled; any one off means it is not.
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-08-15 (2 months ago)source
- CVSS
- 7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.13%, higher than 2.3% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/s390
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.15 | 5.15.216 | 8fb69547924b |
| 5.15 | 6.1.183 | 3ea5210db058 |
| 5.15 | 6.6.151 | 4e4816882581 |
| 5.15 | 6.12.103 | b40c74262f7e |
| 5.15 | 6.18.44 | bd63c7879eaa |
| 5.15 | 7.1.8 | 93a0a846ec59 |
| 5.15 | 7.2 | d211028bac1b |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4788-1 | 2026-09-19 | bookworm 6.12.107-1~deb12u1 | tracker |
| DLA-4777-1 | 2026-09-08 | bookworm 6.1.187-1 | tracker |
| DSA-6466-1 | 2026-08-25 | trixie 6.12.105-1 | tracker |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:LAttack vector, local
- Exploitation requires a local ioctl(2) on a qeth network interface via socket(SIOCDEVPRIVATE+5..+7); the path is sock_ioctl() -> dev_ioctl() -> dev_siocdevprivate() -> qeth_siocdevprivate() with no remote packet or network protocol entry point.
- AC:LAttack complexity, low
- Any local user who can open an AF_INET socket and name a qeth netdev can invoke these ioctls deterministically; no races, special memory layout, or rare kernel configuration is required beyond s390 hardware with qeth present.
- PR:LPrivileges required, low
- The bug is missing CAP_NET_ADMIN in qeth_siocdevprivate(); generic SIOCDEVPRIVATE handling in dev_ioctl() performs no capability check, so any unprivileged local account on an IBM Z/LinuxONE LPAR can reach these handlers without root or namespace-granted admin rights.
- UI:NUser interaction, none
- Exploitation needs only the attacker opening a socket and issuing ioctl against a qeth interface; no victim login, mount, or other interactive action is required on a shared mainframe guest.
- S:UScope, unchanged
- Impact stays within kernel/driver control of the local OSA/QDIO adapter and does not cross a VM, container, or IOMMU security boundary; this is standard local privilege and hardware-management misuse, not a guest-to-host escape.
- C:HConfidentiality impact, high
- SIOC_QETH_QUERY_OAT and SIOC_QETH_ADP_SET_SNMP_CONTROL copy OSA Express firmware response buffers (link attributes, adapter operational data, SNMP MIB objects, card-type details) to unprivileged userspace, disclosing network hardware management information normally restricted to administrators.
- I:HIntegrity impact, high
- SIOC_QETH_ADP_SET_SNMP_CONTROL accepts attacker-controlled qeth_snmp_cmd request/data and forwards IPA_SETADP_SET_SNMP_CONTROL commands to OSA firmware, letting unprivileged users alter adapter SNMP/management state on production IBM Z network interfaces.
- A:HAvailability impact, high
- Handlers honor attacker-chosen buffer sizes (kzalloc(udata_len) in qeth_snmp_command and vzalloc(buffer_len) in qeth_query_oat_command without upper bounds), enabling repeated large allocations for kernel memory exhaustion/OOM, and malformed IPA commands can disrupt adapter operation.