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CVE-2026-90142
virtio_net: Fix resize of the RX ring
Published 2026-09-17 (31 days ago) by the Linux kernel CNA. Subsystem drivers/net. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-90142 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 | vulnerable | 6.12.113-1 | No fix published anywhere yet, neither in Debian nor upstream for the series trixie tracks. Watch the Debian tracker page for this CVE. Advisories for trixie have historically landed a median of 11 days after publication. |
| 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. |
The vulnerability
What the bug is
When a AF_XDP socket is attached, the virtnet_rx_resize should resize the rq->xsk_buffs XSK buffer array. Otherwise, when the size grows, the virtnet_rx_resume() causes a write past the end of the array. This is easily reproducable with ethtool -G ens3 rx 32 ./xdpsock -i eth0 -q 0 -r -z & ethtool -G eth0 rx 256
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/virtio_net.c
- What this is
- VIRTIO NET DRIVERMAINTAINERS section matched on drivers/net/virtio_net.c · netdev@vger.kernel.org · Maintained
- Kernel module
- virtio_net
Check it on the machine
grep -w CONFIG_VIRTIO_NET /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 virtio_netPrints 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 as a loadable module. Every release below compiles it as a module on every flavour, so whether the code is in the running kernel depends on whether that module is loaded.
- bookworm, trixie, forky, sidm
- m
- a loadable module on every flavour - check lsmod, can be blacklisted
- Build switch
- CONFIG_VIRTIO_NET
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
- 2026-09-17 (31 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
- 0.17%, higher than 6.3% 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 |
|---|---|---|
| 6.11 | 6.18.57 | 5235abdb760b |
| 6.11 | 7.2.6 | 8344c9233c8f |
| 6.11 | 7.3 | d09c98a6da21 |
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 overflow is driven by ring->rx_pending passed to virtnet_set_ringparam() from SIOCETHTOOL ETHTOOL_SRINGPARAM (ethtool_set_ringparam) or ETHTOOL_MSG_RINGS_SET (ethnl_set_rings), after virtnet_xsk_pool_enable() sized rq->xsk_buffs from AF_XDP bind(); received packets never supply the new vring length.
- AC:LAttack complexity, low
- The reporter's sequence (ethtool -G rx 32, xdpsock -z, ethtool -G rx 256) deterministically grows the vring while leaving xsk_buffs at the old size; virtnet_rx_resume()->try_fill_recv()->virtnet_add_recvbuf_xsk() then passes rq->vq->num_free to xsk_buff_alloc_batch(). The attacker controls both sizes and the UMEM fill ring; there is no race.
- PR:LPrivileges required, low
- ETHTOOL_MSG_RINGS_SET is GENL_UNS_ADMIN_PERM (netlink_ns_capable CAP_NET_ADMIN) and the ioctl path checks ns_capable(net->user_ns, CAP_NET_ADMIN); AF_XDP socket() checks ns_capable(net->user_ns, CAP_NET_RAW) in xsk_create(). Both are available in a user-owned netns that holds the virtio_net device, not init-namespace root.
- UI:NUser interaction, none
- The attacker themselves issues the ethtool ring-resize ioctl/netlink and bind()s the AF_XDP zero-copy socket (xdpsock -z) that calls virtnet_xsk_pool_enable(); no separate victim action such as mounting media is required.
- S:UScope, unchanged
- virtnet_add_recvbuf_xsk() overflows rq->xsk_buffs in the same kernel that hosts the virtio_net frontend. That is guest-kernel heap corruption, not a KVM/vhost guest-to-host escape or IOMMU bypass.
- C:HConfidentiality impact, high
- After virtqueue_resize(), xsk_buff_alloc_batch() writes up to the new vring's num_free xdp_buff* values past the old xsk_buffs kvzalloc, corrupting adjacent heap objects with kernel pointers that can be turned into an arbitrary read.
- I:HIntegrity impact, high
- The same out-of-bounds xdp_buff* write, and the virtqueue_add_inbuf_premapped() loop that then consumes xsk_buffs[i] through that overflowed range, is kernel heap corruption usable for an arbitrary write or control-flow hijack.
- A:HAvailability impact, high
- The heap overflow in virtnet_add_recvbuf_xsk() during virtnet_rx_resume() after virtqueue_resize() is a kernel memory-safety violation that oopses or panics even without a full exploit, matching the commit's write-past-end.