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CVE-2026-80646
ipv6: guard against possible NULL deref in __in6_dev_stats_get()
Published 2026-08-28 (2 months ago) by the Linux kernel CNA. Subsystem include/net. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-80646 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 | fixed | 6.1.180-1 | Update the kernel and reboot. Fixed in 6.1.180-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.100-1 | Update the kernel and reboot. Fixed in 6.12.100-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
dev_get_by_index_rcu() could return NULL if the original physical device is unregistered. Found by Sashiko.
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.
include/net/addrconf.h
- What this is
- NETWORKING [IPv4/IPv6]MAINTAINERS section matched on include/net/addrconf.h · netdev@vger.kernel.org · Maintained
Show whether Debian builds this, per release
Not established. This site could not find the build rule for the affected file in the kernel trees Debian ships, so it has no answer about whether Debian compiles this code. Read that as unknown, never as absent.
- bookworm, trixie, forky, sid?
- ?
- not established - no Makefile entry for the affected file
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.
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
Signals
- Published
- 2026-08-28 (2 months ago)source
- CVSS
- 7.5 high
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsource recompute it - Attack vector
- network (AV:N)source
- EPSS
- 0.72%, higher than 52.9% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- include/net
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.2 | 5.10.261 | a23f2c68c663 |
| 5.2 | 5.15.212 | e14db4367794 |
| 5.2 | 6.1.178 | 1a4adfbeb47a |
| 5.2 | 6.6.145 | 1e3db30a8881 |
| 5.2 | 6.12.97 | 952426a83ca7 |
| 5.2 | 6.18.40 | 0db1949084e8 |
| 5.2 | 7.1.5 | fc920c0659cd |
| 5.2 | 7.2 | 507541c2a8ee |
| 4.19.291 | 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:NAttack vector, network
- Remote attackers reach ipv6_frag_rcv() through the standard IPv6 receive and local-delivery path (ipv6_rcv to ip6_protocol_deliver_rcu) by sending fragmented IPv6 packets to an Internet-facing host running IPv6 reassembly on a VRF/L3-master ingress path.
- AC:LAttack complexity, low
- An attacker can repeatedly deliver IPv6 fragments and time them against concurrent netdev unregister (link teardown, container veth removal, or ip link del with CAP_NET_ADMIN in a user namespace), controlling both sides of the race rather than depending on uncontrollable layout.
- PR:NPrivileges required, none
- Sending unauthenticated IPv6 fragments requires no kernel credentials; VRF/L3-master configuration is a deployment condition on routers and cloud hosts, not a privilege the attacker must hold to deliver the triggering traffic.
- UI:NUser interaction, none
- Exploitation needs only network delivery of fragmented IPv6 packets during interface teardown; no victim action such as opening files, clicking links, or mounting filesystems is required.
- S:UScope, unchanged
- The NULL dereference crashes the kernel on the receiving host but does not cross a VM, container, or IOMMU security boundary; impact stays within the same kernel security authority.
- C:NConfidentiality impact, none
- The failure is a NULL pointer read in __in6_dev_get(NULL) after dev_get_by_index_rcu() returns NULL; there is no use-after-free, out-of-bounds read, or other information-disclosure primitive.
- I:NIntegrity impact, none
- The bug dereferences a NULL net_device pointer for statistics lookup only; it provides no memory write, corruption, or control-flow hijack primitive beyond crashing the kernel.
- A:HAvailability impact, high
- The NULL dereference during IPv6 fragment receive/reassembly processing in softirq context causes a kernel OOPS or panic, fully denying availability on the affected system until reboot.