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CVE-2026-68440
net: txgbe: fix heap overflow when reading module EEPROM
Published 2026-08-12 (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-2026-68440 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 | 7.1.6-1 | Update the kernel and reboot. Fixed in 7.1.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.6-1 | Update the kernel and reboot. Fixed in 7.1.6-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
txgbe_read_eeprom_hostif() always copies round_up(length, 4) bytes into the caller buffer, which ethtool allocates with exactly 'length' bytes. A non-4-aligned length therefore causes an out-of-bounds write. Copy only the remaining bytes on the final dword instead.
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/wangxun/txgbe/txgbe_aml.c
- What this is
- WANGXUN ETHERNET DRIVERMAINTAINERS section matched on drivers/net/ethernet/wangxun/ · netdev@vger.kernel.org · Maintained
Check it on the machine
grep -wE 'CONFIG_ETHERNET|CONFIG_NET_VENDOR_WANGXUN|CONFIG_TXGBE' /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 2 releases. The build rule could not be established for 2 releases, so nothing is claimed about those.
- bookworm, trixie?
- forky, sidn
- ?
- not established - no Makefile entry for the affected file
- n
- not enabled on any flavour - this release does not build the code
Where a release above reads "not established", no build rule for the affected file was found in that release's kernel tree. That is a gap in this lookup, not a finding that the code is absent.
- Build switches
- CONFIG_ETHERNET, CONFIG_NET_VENDOR_WANGXUN, CONFIG_TXGBE
- 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
- 2026-08-12 (2 months 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
- 0.12%, higher than 1.9% 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 |
|---|---|---|
| 6.19 | 7.1.6 | febcced69581 |
| 6.19 | 7.2 | 6a905a71fd43 |
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 bug is triggered through the ethtool genetlink interface (ETHTOOL_MSG_MODULE_EEPROM_GET) from a local socket; no network packet or remote peer data reaches the vulnerable copy loop.
- AC:LAttack complexity, low
- The attacker fully controls the request length attribute (policy allows 1..128 with no alignment constraint), so any non-4-aligned value deterministically triggers the over-copy on every call, repeatably and without racing.
- PR:LPrivileges required, low
- The ethtool op is gated by GENL_UNS_ADMIN_PERM, i.e. ns-capable CAP_NET_ADMIN in the user namespace owning the netdev's netns, which an unprivileged user can obtain via unshare -Urn rather than real root.
- UI:NUser interaction, none
- The attacker issues the ethtool netlink request directly; no victim action, module plug event, or administrator step is needed.
- S:UScope, unchanged
- The out-of-bounds write corrupts kernel heap memory within the same kernel security authority; no VM, IOMMU, or sandbox boundary is crossed.
- C:HConfidentiality impact, high
- The overflow is a heap memory-corruption primitive adjacent to attacker-groomable slab objects, and corrupting neighbouring object metadata (lengths, pointers) can be leveraged to disclose arbitrary kernel memory back through the same ethtool reply.
- I:HIntegrity impact, high
- This is an out-of-bounds heap write with firmware/module-supplied bytes past the end of a caller-sized kmalloc buffer, giving an attacker-triggerable corruption of adjacent kernel data that can be steered toward control-flow hijacking.
- A:HAvailability impact, high
- Corrupting adjacent slab objects or allocator metadata leads to kernel oops/panic, and on KASAN or hardened configurations the slab-out-of-bounds write itself aborts the kernel, so a repeatable denial of service is available.