Look up another CVE · open CVE-2026-72064 in the interactive tracker
CVE-2026-72064
net: mana: Sync page pool RX frags for CPU
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem drivers/net. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-72064 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 | not affected | 6.1.190-1 | Nothing to do. bookworm never shipped the vulnerable code. |
| Debian 13trixie | not affected | 6.12.113-1 | Nothing to do. trixie never shipped the vulnerable code. |
| Debian 14forky | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
MANA allocates RX buffers from page pool fragments when frag_count is greater than 1. In that case the buffers remain DMA mapped by page pool and the RX completion path does not call dma_unmap_single(). As a result, the implicit sync-for-CPU normally performed by dma_unmap_single() is missing before the packet data is passed to the networking stack. This breaks RX on configurations which require explicit DMA syncing, for example when booted with swiotlb=force. Fix this by recording the page pool page and DMA sync offset when the RX buffer is allocated, and syncing the received packet range for CPU access before handing the RX buffer to the stack.
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/microsoft/mana/mana_en.c
include/net/mana/mana.h
- What this is
- Hyper-V/Azure CORE AND DRIVERSMAINTAINERS section matched on drivers/net/ethernet/microsoft/ · linux-hyperv@vger.kernel.org · Supported
- Kernel module
- mana
Check it on the machine
grep -wE 'CONFIG_ETHERNET|CONFIG_MICROSOFT_MANA|CONFIG_NET_VENDOR_MICROSOFT' /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 manaPrints 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 builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.
- bookwormMnot built on armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, i386/686, i386/686-pae, i386/rt/686-pae, ppc64el/powerpc64le
- trixieMnot built on armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- forky, sidMnot built on armhf/armmp, armhf/armmp-lpae, loong64/loong64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_ETHERNET, CONFIG_MICROSOFT_MANA, CONFIG_NET_VENDOR_MICROSOFT
- 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
- 9.8 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- network (AV:N)source
- EPSS
- 0.65%, higher than 50.1% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- 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 |
|---|---|---|
| 6.18 | 6.18.56 | 845c959178cc |
| 6.18 | 7.1.5 | bc650dd5ce64 |
| 6.18 | 7.2 | c72a0f09c57f |
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:NAttack vector, network
- The bug is in the MANA Ethernet RX completion path (MSI-X/NAPI → mana_process_rx_cqe → mana_refill_rx_oob → mana_rx_skb) on Azure/cloud VMs; any remote host that can send IP traffic to the MANA interface drives packet reception before authentication or local privilege checks.
- AC:LAttack complexity, low
- On deployments where DMA needs explicit CPU sync (e.g. swiotlb=force or non-coherent DMA), every received frame on the default standard-MTU page-pool-fragment path (frag_count>1) deterministically skips sync; the attacker only sends network packets with no race, layout gamble, or timing window.
- PR:NPrivileges required, none
- Exploitation requires no credentials or local access; the vulnerable code runs in hardware interrupt/NAPI context on inbound packets and is not gated by capabilities, netlink, ioctl, or user namespaces.
- UI:NUser interaction, none
- Packet reception and handoff to the networking stack occur automatically once the MANA interface is up; no victim mount, click, or other administrative action is required beyond normal network operation.
- S:UScope, unchanged
- Impact is confined to incorrect/stale packet data processed inside the same guest kernel and network stack; it does not cross a VM-host, IOMMU, or other separate security boundary.
- C:HConfidentiality impact, high
- Without dma_sync_for_cpu the CPU can read stale cache or bounce-buffer contents for the full received length (up to MTU) instead of hardware-written data, disclosing prior RX buffer or unrelated DMA residue to the stack, XDP, or applications.
- I:HIntegrity impact, high
- The skb handed upward can contain bytes that differ from the frame the NIC actually wrote, corrupting protocol parsing and application-visible payload integrity across the entire packet, not just a bounded tail region.
- A:HAvailability impact, high
- On configurations requiring explicit DMA syncing the driver commit reports RX is broken entirely; a remote sender can repeatedly trigger the faulty path and deny reliable receive on the MANA interface.