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CVE-2026-72065
net: mana: Validate the packet length reported by the NIC
Published 2026-08-15 (2 months 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-2026-72065 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 | fixed | 6.12.101-1 | Update the kernel and reboot. Fixed in 6.12.101-1. A running kernel keeps the old code until the machine restarts. |
| 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. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4745-1 · 2026-08-18 · text | 6.12.101-1~deb12u1 | Update the kernel and reboot. DLA-4745-1 shipped the fix on 2026-08-18, in 6.12.101-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
Validate the packet length reported in the RX CQE before passing it to skb processing. The CQE is supplied by the NIC device and should not be blindly trusted.
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
- 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
- bookworm · linux-6.12Mnot built on armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k
- 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
- 0.73%, higher than 53.3% 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 |
|---|---|---|
| 5.13 | 5.15.217 | a631f82f89c7 |
| 5.13 | 6.1.184 | d2568e64d01f |
| 5.13 | 6.6.148 | 2e276b14b6d3 |
| 5.13 | 6.12.101 | 6080189291d9 |
| 5.13 | 6.18.42 | 6d13eaa13341 |
| 5.13 | 7.1.5 | 282c5214ca4e |
| 5.13 | 7.2 | 2e2a83b4998a |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4777-1 | 2026-09-08 | bookworm 6.1.187-1 | tracker |
| DLA-4745-1 | 2026-08-18 | bookworm 6.12.101-1~deb12u1 | 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:NAttack vector, network
- On internet-facing Azure VMs, remote packets drive MANA RX through IRQ/NAPI into mana_poll_rx_cq()/mana_process_rx_cqe(), where device-written RX CQE pkt_len is trusted and passed to skb/XDP processing without bounds checks against rxq->datasize.
- AC:LAttack complexity, low
- The attacker can repeatedly send traffic to trigger RX completions until the MANA backend reports pkt_len above rxq->datasize; once that CQE arrives, mana_refill_rx_oob() and mana_rx_skb() misuse the length deterministically with no race or special memory layout.
- PR:NPrivileges required, none
- The vulnerable path is the netdev NAPI receive handler before any socket or credential checks; an unauthenticated remote sender only needs packets routed to the VM's MANA interface, with no local account or capability on the victim.
- UI:NUser interaction, none
- RX CQEs are handled automatically from hardware interrupts and NAPI polling once the interface is up; no victim mount, ioctl, or other interactive action is required beyond normal network reception.
- S:UScope, unchanged
- Out-of-bounds access and crashes occur in the guest kernel processing MANA RX buffers; impact stays within that kernel security authority and does not by itself cross a VM/host or IOMMU boundary.
- C:HConfidentiality impact, high
- Unchecked pkt_len is used in page_pool_dma_sync_for_cpu(), xdp_prepare_buff()/bpf_prog_run_xdp(), and skb_put()/eth_type_trans(), enabling reads well past the DMA-mapped rxq->datasize region and leaking adjacent kernel heap/page memory.
- I:HIntegrity impact, high
- Oversized pkt_len expands skb and XDP data bounds beyond the posted RX buffer, corrupting adjacent kernel memory and providing attacker-influenced metadata/control corruption primitives consistent with high integrity impact for OOB memory corruption.
- A:HAvailability impact, high
- Processing an oversized pkt_len can kernel oops/panic from skb_put bounds failures or unmapped reads in softirq/NAPI context, and the remote attacker can retrigger the condition for sustained denial of service.