Look up another CVE · open CVE-2026-74737 in the interactive tracker
CVE-2026-74737
net: ethernet: ti: am65-cpsw-nuss: Fix port_id extraction from SRC TAG
Published 2026-08-26 (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-2026-74737 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 | 6.12.105-1 | Update the kernel and reboot. Fixed in 6.12.105-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.10-1 | Update the kernel and reboot. Fixed in 7.1.10-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.10-1 | Update the kernel and reboot. Fixed in 7.1.10-1. 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
On the packet reception path, the ID of the MAC Port on which the packet was received, is embedded in the RX DMA Descriptor's metadata. The ID is extracted using the helper function cppi5_desc_get_tags_ids() which fills in the 16-bit Source Tag into the 'port_id' variable. However, it is only the lower 8-bits of the 16-bit Source Tag that represent the MAC Port ID, while the upper 8-bits are Hardware-Reserved and carry an arbitrary value. With the existing logic, sporadic kernel crash is observed due to the subsequent driver code accessing out-of-bound memory because of an invalid port_id. Hence, fix the port_id extraction logic to use only the lower 8-bits of the Source Tag as the MAC Port ID.
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/ti/am65-cpsw-nuss.c
- What this is
- NETWORKING DRIVERSMAINTAINERS section matched on drivers/net/ · netdev@vger.kernel.org · Maintained
- Kernel module
- ti_am65_cpsw_nuss
Check it on the machine
grep -wE 'CONFIG_ETHERNET|CONFIG_NET_VENDOR_TI|CONFIG_TI_K3_AM65_CPSW_NUSS' /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 ti_am65_cpsw_nussPrints 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.
- bookwormMnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt/amd64, arm64/cloud-arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, i386/686, i386/686-pae, i386/rt/686-pae, ppc64el/powerpc64le
- trixieMnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt/amd64, arm64/cloud-arm64, armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- forky, sidn
- bookworm · linux-6.12Mnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt/amd64, arm64/cloud-arm64, 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
- n
- not enabled on any flavour - this release does not build the code
- Build switches
- CONFIG_ETHERNET, CONFIG_NET_VENDOR_TI, CONFIG_TI_K3_AM65_CPSW_NUSS
- 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
- 2026-08-26 (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
- 0.55%, higher than 44.9% 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 |
|---|---|---|
| 5.7 | 5.10.266 | 14fc40bf2839 |
| 5.7 | 5.15.217 | 1c0e35ce7611 |
| 5.7 | 6.1.184 | 9a220225efd6 |
| 5.7 | 6.6.153 | 551688b410d3 |
| 5.7 | 6.12.105 | 46a8e084a159 |
| 5.7 | 6.18.46 | 72e4e3d7efc3 |
| 5.7 | 7.1.10 | 914e0100df34 |
| 5.7 | 7.2 | 36a05d282007 |
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 |
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 am65_cpsw_nuss_rx_packets() on the NAPI RX path for TI AM65/J721E CPSW Ethernet; any remote host that can deliver L2 frames to a configured port triggers RX DMA completion and this handler without local access.
- AC:LAttack complexity, low
- An attacker only needs to send Ethernet traffic to drive RX completions; although hardware upper source-tag bits make hits sporadic, sustained transmission reliably provokes the out-of-bounds port lookup without races or victim-specific state.
- PR:NPrivileges required, none
- Exploitation requires no Linux credentials or capabilities—the vulnerable code runs in kernel RX softirq before socket demux or authentication, reachable by any entity that can send frames to the NIC.
- UI:NUser interaction, none
- Packet reception and NAPI polling are automatic once the interface is up; no victim mount, click, or other local action is needed beyond normal network connectivity to the device.
- S:UScope, unchanged
- Impact is kernel memory corruption and crash within the host kernel security domain; there is no VM, container, or IOMMU boundary crossover typical of Scope Changed scenarios.
- C:HConfidentiality impact, high
- Invalid port_id indexes far past the kmalloc'd ports[] array (max eight) via am65_common_get_port(), causing out-of-bounds reads of adjacent kernel objects such as ndev pointers, xdp_prog, and other port fields.
- I:HIntegrity impact, high
- The same out-of-bounds port pointer drives writes including ndev stats increments, XDP processing, and skb association on attacker-supplied packet buffers, yielding a memory corruption primitive steerable toward kernel modification.
- A:HAvailability impact, high
- The fix commit documents sporadic kernel oops/panics from out-of-bounds access when hardware source-tag upper bits inflate port_id beyond the small allocated ports array.