Look up another CVE · open CVE-2026-64077 in the interactive tracker
CVE-2026-64077
netfilter: ebtables: move to two-stage removal scheme
Published 2026-07-19 (3 months ago) by the Linux kernel CNA. Subsystem net/bridge. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-64077 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 | 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 | 7.0.12-1 | Update the kernel and reboot. Fixed in 7.0.12-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.0.12-1 | Update the kernel and reboot. Fixed in 7.0.12-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
Like previous patches for x_tables, follow same pattern in ebtables. We can't reuse xt helpers: ebt_table struct layout is incompatible. table->ops assignment is now done while still holding the ebt mutex to make sure we never expose partially-filled table struct.
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/bridge/netfilter/ebtable_broute.c
net/bridge/netfilter/ebtable_filter.c
net/bridge/netfilter/ebtable_nat.c
net/bridge/netfilter/ebtables.c
- What this is
- NETFILTERMAINTAINERS section matched on net/*/netfilter/ · netfilter-devel@vger.kernel.org · Maintained
- Kernel module
- ebtable_broute
Check it on the machine
grep -wE 'CONFIG_BRIDGE|CONFIG_BRIDGE_EBT_BROUTE|CONFIG_NETFILTER' /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 ebtable_broutePrints 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 2 releases, so the answer depends on which release the machine runs.
- bookworm, trixiem
- forky, sidn
- m
- a loadable module on every flavour - check lsmod, can be blacklisted
- n
- not enabled on any flavour - this release does not build the code
- Build switches
- CONFIG_BRIDGE, CONFIG_BRIDGE_EBT_BROUTE, CONFIG_NETFILTER
- 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
- 2026-07-19 (3 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
- 0.17%, higher than 6.3% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- net/bridge
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.15 | 6.18.34 | 739d5dac7b2d |
| 5.15 | 7.0.11 | ef395579a763 |
| 5.15 | 7.1 | b7f0544d86d4 |
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 reached through ebtables setsockopt/getsockopt administration syscalls (do_ebt_set_ctl/do_ebt_get_ctl), not through processing of remotely received network or bridge frames.
- AC:LAttack complexity, low
- An attacker can reliably win the race by running concurrent threads—one issuing ebtables setsockopt to register or modify a table while another destroys the network namespace or triggers module teardown.
- PR:LPrivileges required, low
- All entry paths require CAP_NET_ADMIN in the target network namespace, which an unprivileged local attacker can obtain via user+network namespaces (unshare -Urn).
- UI:NUser interaction, none
- Exploitation requires no action from any other user or administrator beyond the attacker’s own local namespace and sockopt operations.
- S:UScope, unchanged
- Impact is confined to kernel memory and privileges on the host; this is a standard kernel race/UAF issue, not a VM, container, or IOMMU boundary escape.
- C:HConfidentiality impact, high
- The missing two-stage removal allows concurrent setsockopt to use an ebt_table while __ebt_unregister_table() frees its backing structures, creating a use-after-free that can be leveraged for arbitrary kernel memory disclosure.
- I:HIntegrity impact, high
- The teardown race and partially-initialized table exposure enable heap use-after-free conditions that can be developed into arbitrary kernel memory writes or code execution via heap grooming.
- A:HAvailability impact, high
- The NULL ops race causes a general protection fault in nf_unregister_net_hooks(), and the concurrent teardown UAF can trigger kernel oops, panic, or denial of service.