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CVE-2026-80991
net: ravb: serialize PTP clock teardown
Published 2026-09-11 (37 days ago) by the Linux kernel CNA. Subsystem drivers/net. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-80991 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 | vulnerable | 6.1.190-1 | No fix published anywhere yet, neither in Debian nor upstream for the series bookworm tracks. Watch the Debian tracker page for this CVE. Advisories for bookworm have historically landed a median of 23 days after publication. |
| Debian 13trixie | fixedDSA-6528-1 · 2026-09-29 · text | 6.12.111-1 | Update the kernel and reboot. DSA-6528-1 shipped the fix on 2026-09-29, in 6.12.111-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4817-1 · 2026-10-04 · text | 6.12.111-1~deb12u1 | Update the kernel and reboot. DLA-4817-1 shipped the fix on 2026-10-04, in 6.12.111-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
ravb_ptp_interrupt() can race with ravb_ptp_stop() and pass the clock to ptp_clock_event() while ptp_clock_unregister() is freeing it. This can lead to a use-after-free. Use READ_ONCE() and WRITE_ONCE() for lockless access to the clock pointer. Atomically detach it with xchg() before disabling PTP interrupts, then synchronize all IRQs which can invoke ravb_ptp_interrupt() before unregistering the detached clock. A handler which read the old pointer completes before the clock is unregistered, while later handlers read NULL and skip the event.
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/renesas/ravb.h
drivers/net/ethernet/renesas/ravb_main.c
drivers/net/ethernet/renesas/ravb_ptp.c
- What this is
- RENESAS ETHERNET AVB DRIVERMAINTAINERS section matched on drivers/net/ethernet/renesas/ravb* · netdev@vger.kernel.org · Maintained
- Kernel module
- ravb
Check it on the machine
grep -wE 'CONFIG_ETHERNET|CONFIG_NET_VENDOR_RENESAS|CONFIG_RAVB' /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 ravbPrints 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 3 releases. It does build it in 2 releases, so the answer depends on which release the machine runs.
- bookworm, trixien
- forky, sidMnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt-amd64, arm64/cloud-arm64, armhf/armmp, armhf/armmp-lpae, loong64/loong64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- 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_ETHERNET, CONFIG_NET_VENDOR_RENESAS, CONFIG_RAVB
- 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
- 2026-09-11 (37 days 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
- 0.16%, higher than 5.2% 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 |
|---|---|---|
| 4.2 | 6.12.109 | 695acb5534a9 |
| 4.2 | 6.18.50 | 67a82e6f886b |
| 4.2 | 7.2.4 | 66b50c31419e |
| 4.2 | 7.3 | 1cb9663789c5 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4817-1 | 2026-10-04 | bookworm 6.12.111-1~deb12u1 | tracker |
| DSA-6528-1 | 2026-09-29 | trixie 6.12.111-1 | 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
- The UAF is reached from the ravb gPTP IRQ handler (ravb_interrupt/ravb_multi_interrupt → ravb_ptp_interrupt → ptp_clock_event) racing local ravb_ptp_stop teardown (close, suspend, TX-timeout work, ethtool ringparam). GIS_PTCF capture IRQs come from the on-chip AVB timer, not from parsing received Ethernet frames.
- AC:LAttack complexity, low
- The attacker drives both sides: ordinary sockets or automotive idle autosuspend trigger ravb_ptp_stop, and PTP_EXTTS_REQUEST on /dev/ptpX (write fd, no CAP_SYS_TIME) enables capture IRQs. Pre-fix stop cleared GIC then called ptp_clock_unregister without synchronize_irq, so an in-flight handler can be raced repeatedly.
- PR:LPrivileges required, low
- On Renesas R-Car/RZ automotive and industrial systems, unprivileged traffic arms ravb_tx_timeout_work and platform autosleep calls ravb_close without CAP_NET_ADMIN; EXTTS enable needs only a writable PTP chardev, not host root. This matches CVE-2025-21801 and CVE-2023-52509 ravb scoring.
- UI:NUser interaction, none
- Interface teardown runs from the TX watchdog or from automatic suspend/idle power management on the affected platforms, with no separate victim user action required.
- S:UScope, unchanged
- The use-after-free corrupts the host kernel's struct ptp_clock heap object within a single kernel security authority and does not cross a VM, IOMMU, or sandbox boundary.
- C:HConfidentiality impact, high
- ptp_clock_event takes ptp->tsevqs_lock and walks the timestamp queue list after ptp_clock_release has kfree'd the clock, so reclaiming that slab provides an arbitrary kernel-memory read primitive.
- I:HIntegrity impact, high
- The same IRQ-context UAF writes via enqueue_external_timestamp into list-queue objects the attacker can reclaim, yielding a kernel heap write primitive suitable for control-flow hijacking.
- A:HAvailability impact, high
- Use-after-free of struct ptp_clock in hardirq context causes a kernel oops or panic and takes down the system's primary Ethernet interface.