Look up another CVE · open CVE-2026-90225 in the interactive tracker
CVE-2026-90225
nfc: llcp: read llcp_sock->local under the socket lock in getsockopt
Published 2026-09-17 (31 days ago) by the Linux kernel CNA. Subsystem net/nfc. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-90225 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 | fixedDLA-4841-1 · 2026-10-17 · text | 6.1.190-1 | Update the kernel and reboot. DLA-4841-1 shipped the fix on 2026-10-17, in 6.1.190-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixedDSA-6528-1 · 2026-09-29 · text | 6.12.111-1 | Update the kernel and reboot. DSA-6528-1 shipped the fix on 2026-09-29, in 6.12.111-1. A running kernel keeps the old code until the machine restarts. |
| 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. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4817-1 · 2026-10-04 · text | 6.12.111-1~deb12u1 | Update the kernel and reboot. DLA-4817-1 shipped the fix on 2026-10-04, in 6.12.111-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
nfc_llcp_getsockopt() read llcp_sock->local before lock_sock(sk) and then dereferenced the cached pointer inside the locked region. llcp_sock_bind() assigns and clears llcp_sock->local under the same socket lock, dropping the last reference on its error path. A getsockopt() racing an in-flight bind() can observe the pointer, block on lock_sock(), and then dereference a freed nfc_llcp_local once bind() has unwound. Move the llcp_sock->local read and the NULL check inside the lock_sock(sk) region so bind() cannot mutate or free the pointer between the load and the use.
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/nfc/llcp_sock.c
- What this is
- NFC SUBSYSTEMMAINTAINERS section matched on net/nfc/ · oe-linux-nfc@lists.linux.dev · Maintained
- Kernel module
- nfc
Check it on the machine
grep -w CONFIG_NFC /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 nfcPrints 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, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.
- bookworm, trixie, forky, sid, bookworm · linux-6.12Mnot built on amd64/cloud-amd64, arm64/cloud-arm64
- M
- a module where it is built at all; some flavours do not build it
- Build switch
- CONFIG_NFC
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
- 0.18%, higher than 6.7% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- net/nfc
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 3.10 | 5.10.270 | 56fd158fef20 |
| 3.10 | 5.15.221 | 8ba8cec05867 |
| 3.10 | 6.1.188 | ed5240bab346 |
| 3.10 | 6.6.157 | fe65727a4a21 |
| 3.10 | 6.12.110 | 2d8ac24565be |
| 3.10 | 6.18.52 | 156e65bd2930 |
| 3.10 | 7.2.6 | d1b73962675c |
| 3.10 | 7.3 | 36812527052c |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4841-1 | 2026-10-17 | bookworm 6.1.190-1 | tracker |
| DLA-4817-1 | 2026-10-04 | bookworm 6.12.111-1~deb12u1 | tracker |
| DSA-6528-1 | 2026-09-29 | trixie 6.12.111-1 | tracker |
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 UAF is triggered by racing local syscalls on an AF_NFC LLCP socket: getsockopt(2) (__sys_getsockopt → do_sock_getsockopt → nfc_llcp_getsockopt) against bind(2) (__sys_bind → llcp_sock_bind). No LLCP PDU or other NFC-peer bytes are consumed on this path, so an adjacent radio peer cannot drive it.
- AC:LAttack complexity, low
- The attacker owns both sides of the lock_sock(sk) race: one thread calls bind() with service_name_len 0 so nfc_llcp_get_sdp_ssap() returns LLCP_SAP_MAX after llcp_sock->local is stored, and another calls getsockopt(SOL_NFC, NFC_LLCP_RW) on the same socket, which used to snapshot that pointer before taking the lock.
- PR:LPrivileges required, low
- llcp_sock_create() checks capable(CAP_NET_RAW) only for SOCK_RAW; nfc_llcp_getsockopt is on llcp_sock_ops for SOCK_STREAM/DGRAM. An unprivileged user in init_net can socket(AF_NFC, SOCK_STREAM, NFC_SOCKPROTO_LLCP) then bind/getsockopt. nfc_llcp_find_local() needs a registered NFC device, which is typical on phones.
- UI:NUser interaction, none
- The attacker creates the AF_NFC LLCP socket and issues bind() and getsockopt() on that fd themselves; no other user needs to tap a tag, mount media, or accept a connection.
- S:UScope, unchanged
- The freed object is the host kernel's kmalloc'd nfc_llcp_local used by nfc_llcp_getsockopt(); impact stays inside the kernel's security authority, not a VM, IOMMU, or sandbox escape.
- C:HConfidentiality impact, high
- nfc_llcp_getsockopt() dereferences the dangling nfc_llcp_local to read local->rw, local->miux, local->remote_miu, and local->remote_lto and copies those values to userspace with put_user(), so reclaim of the freed slab yields an arbitrary-read primitive.
- I:HIntegrity impact, high
- llcp_sock_bind()'s sock_llcp_put_local path drops nfc_llcp_local via nfc_llcp_local_put() while nfc_llcp_getsockopt() still holds the pointer; reclaiming that kmalloc object with attacker-controlled data turns the dangling local into a write/control-flow primitive.
- A:HAvailability impact, high
- Using the freed nfc_llcp_local in nfc_llcp_getsockopt() (the local->rw and local->remote_lto loads) is a kernel slab UAF that oopses or panics on KASAN/SLUB_DEBUG and can crash the system even when not fully exploited.