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CVE-2026-64587
net: ethernet: arc: emac: quiesce interrupts before requesting IRQ
Published 2026-08-06 (2 months ago) by the Linux kernel CNA. Subsystem drivers/net. Debian urgency: not yet assigned.
Debian does not build this code. The per-release build detail is under "Where it lives" below.
What to do, per Debian release
Debian's own status for CVE-2026-64587 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 | fixed | 6.1.170-1 | Update the kernel and reboot. Fixed in 6.1.170-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.85-1 | Update the kernel and reboot. Fixed in 6.12.85-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 6.19.10-1 | Update the kernel and reboot. Fixed in 6.19.10-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 6.19.10-1 | Update the kernel and reboot. Fixed in 6.19.10-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
Normal RX/TX interrupts are enabled later, in arc_emac_open(), so probe should not see interrupt delivery in the usual case. However, hardware may still present stale or latched interrupt status left by firmware or the bootloader. If probe later unwinds after devm_request_irq() has installed the handler, such a stale interrupt can still reach arc_emac_intr() during teardown and race with release of the associated net_device. Avoid that window by putting the device into a known quiescent state before requesting the IRQ: disable all EMAC interrupt sources and clear any pending EMAC interrupt status bits. This keeps the change hardware-focused and minimal, while preventing spurious IRQ delivery from leftover state.
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/net/ethernet/arc/emac_main.c
- What this is
- NETWORKING DRIVERSMAINTAINERS section matched on drivers/net/ · netdev@vger.kernel.org · Maintained
- Kernel module
- none to look for. The file would have gone into arc_emac, and Debian does not compile it into that module, so finding arc_emac in lsmod would say nothing about this CVE.
Check it on the machine
grep -wE 'CONFIG_ARC_EMAC_CORE|CONFIG_ETHERNET|CONFIG_NET_VENDOR_ARC' /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.
Show whether Debian builds this, per release
Debian does not build this code. In 4 releases below, every kernel flavour Debian publishes has the switch off, so the vulnerable file is compiled into no kernel binary Debian ships.
- bookworm, trixie, forky, sidn
- n
- not enabled on any flavour - this release does not build the code
- Build switches
- CONFIG_ARC_EMAC_CORE, CONFIG_ETHERNET, CONFIG_NET_VENDOR_ARC
- 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
- 2026-08-06 (2 months ago)source
- CVSS
- 7.0 high
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.16%, higher than 4.3% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/net
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 3.11 | 5.10.253 | abd338da658d |
| 3.11 | 5.15.203 | 5f29dd540fe5 |
| 3.11 | 6.1.167 | 6fc744977374 |
| 3.11 | 6.6.130 | 81431da77792 |
| 3.11 | 6.12.78 | d0f2386f5298 |
| 3.11 | 6.18.19 | 8efd5dcd31e2 |
| 3.11 | 6.19.9 | 8f9adb3605e3 |
| 3.11 | 7.0 | 2503d08f8a2d |
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
- The flaw is in ARC/Rockchip EMAC platform probe/teardown (arc_emac_probe → free_netdev while the devm IRQ remains), not in packet processing; a remote or adjacent peer cannot induce this path via Ethernet frames.
- AC:HAttack complexity, high
- Exploitation needs leftover firmware/bootloader-latched EMAC IRQ state plus a post-request_irq probe failure overlapping interrupt delivery; the attacker does not control that hardware/firmware precondition or IRQ timing.
- PR:LPrivileges required, low
- An unprivileged local user can drive post-request_irq failures such as dmam_alloc_coherent -ENOMEM via memory pressure during deferred probe after userspace is up; platform bind/unbind is root-only but is not required for this path.
- UI:NUser interaction, none
- No victim action is required; once leftover IRQ state exists, the attacker can induce probe failure and race teardown without another user opening or configuring the interface.
- S:UScope, unchanged
- Impact is use-after-free/corruption inside the host kernel EMAC interrupt path and does not cross a VM, IOMMU, or other separate security authority.
- C:HConfidentiality impact, high
- arc_emac_intr can run on a freed or half-initialized net_device (netdev_priv, NAPI, stats), a use-after-free that can expose attacker-influenced kernel heap contents.
- I:HIntegrity impact, high
- The same UAF lets the IRQ handler write through reclaimed net_device/NAPI state (e.g. napi_schedule), enabling heap corruption and potential control-flow hijacking.
- A:HAvailability impact, high
- Dereferencing freed or uninitialized NAPI/netdev state in IRQ context can oops or panic the kernel, causing full denial of service.