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CVE-2026-53132
vsock/virtio: fix potential unbounded skb queue
Published 2026-06-25 (4 months ago) by the Linux kernel CNA. Subsystem net/vmw_vsock. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-53132 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 | vulnerable | 6.1.190-1 | No fix published anywhere yet, neither in Debian nor upstream for the series bookworm tracks. Watch the Debian tracker page for this CVE. Advisories for bookworm have historically landed a median of 23 days after publication. |
| Debian 13trixie | fixed | 6.12.94-1 | Update the kernel and reboot. Fixed in 6.12.94-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.0.13-1 | Update the kernel and reboot. Fixed in 7.0.13-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.0.13-1 | Update the kernel and reboot. Fixed in 7.0.13-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
virtio_transport_inc_rx_pkt() checks vvs->rx_bytes + len > vvs->buf_alloc. virtio_transport_recv_enqueue() skips coalescing for packets with VIRTIO_VSOCK_SEQ_EOM. If fed with packets with len == 0 and VIRTIO_VSOCK_SEQ_EOM, a very large number of packets can be queued because vvs->rx_bytes stays at 0. Fix this by estimating the skb metadata size: (Number of skbs in the queue) * SKB_TRUESIZE(0)
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.
net/vmw_vsock/virtio_transport_common.c
- What this is
- VIRTIO AND VHOST VSOCK DRIVERMAINTAINERS section matched on net/vmw_vsock/virtio_transport_common.c · kvm@vger.kernel.org · Maintained
- Kernel module
- vmw_vsock_virtio_transport_common
Check it on the machine
grep -wE 'CONFIG_VIRTIO_VSOCKETS_COMMON|CONFIG_VSOCKETS' /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 vmw_vsock_virtio_transport_commonPrints 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 switches
- CONFIG_VIRTIO_VSOCKETS_COMMON, CONFIG_VSOCKETS
- 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
- 2026-06-25 (4 months ago)source
- CVSS
- 7.1 high
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.14%, higher than 2.9% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- net/vmw_vsock
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.3 | 6.12.94 | 1eca304f97a3 |
| 6.3 | 6.18.36 | 9bdc637fde66 |
| 6.3 | 7.0.13 | 100d5b2ffdc6 |
| 6.3 | 7.1 | 059b7dbd20a6 |
| 6.1.63 | 0 | 0 |
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 vulnerable code is in virtio/vhost-vsock receive handling, reached through a local virtual socket channel rather than ordinary IP networking. The highest reasonable scenario is a malicious KVM guest or local vsock peer supplying crafted virtio-vsock packets to a host vsock endpoint.
- AC:LAttack complexity, low
- Once the attacker can supply virtio-vsock headers, repeatedly sending len=0 OP_RW packets with VIRTIO_VSOCK_SEQ_EOM deterministically bypasses payload accounting. No race, timing window, or rare memory layout condition is required.
- PR:NPrivileges required, none
- The vhost-vsock receive path performs address/type/state validation but no host credential, capability, or authentication check before enqueueing the packet. A malicious guest/peer needs no privileges on the vulnerable host kernel to deliver crafted virtio-vsock packets.
- UI:NUser interaction, none
- No victim user action is required after a reachable vsock endpoint exists. The attacker can flood the receive queue directly.
- S:CScope, changed
- In the vhost-vsock deployment, guest-controlled packets consume host kernel memory, crossing the guest/host security boundary. This is a KVM guest-to-host denial-of-service scenario.
- C:NConfidentiality impact, none
- The bug is unbounded skb queue growth from missing metadata accounting, not an out-of-bounds read, UAF, or data disclosure path. I found no confidentiality primitive.
- I:NIntegrity impact, none
- The flaw queues attacker-supplied zero-length skb metadata but does not corrupt memory or provide an arbitrary write/control-flow primitive. I found no integrity impact beyond denial of service.
- A:HAvailability impact, high
- The receive queue can grow without the intended buffer-accounting limit, causing unbounded host kernel memory consumption. A sustained flood can drive OOM or host-wide service loss.