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CVE-2026-53147
thunderbolt: Validate XDomain request packet size before type cast
Published 2026-06-25 (4 months ago) by the Linux kernel CNA. Subsystem drivers/thunderbolt. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-53147 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-4665-1 · 2026-07-03 · text | 6.1.176-1 | Update the kernel and reboot. DLA-4665-1 shipped the fix on 2026-07-03, in 6.1.176-1. A running kernel keeps the old code until the machine restarts. |
| 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
tb_xdp_handle_request() casts the received packet buffer to protocol-specific structs without verifying that the allocation is large enough for the target type. A peer can send a minimal XDomain packet that passes the generic header length check but is shorter than the struct accessed after the cast, causing out-of- bounds reads from the kmemdup allocation. Plumb the packet length through xdomain_request_work and validate it against the expected struct size before each cast.
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/thunderbolt/xdomain.c
- What this is
- THUNDERBOLT DRIVERMAINTAINERS section matched on drivers/thunderbolt/ · linux-usb@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
- 2026-06-25 (4 months ago)source
- CVSS
- 8.1 high
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Hsource recompute it - Attack vector
- adjacent network (AV:A)source
- EPSS
- 0.27%, higher than 17.6% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/thunderbolt
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 4.15 | 6.1.176 | a770e6292309 |
| 4.15 | 6.6.143 | 0dd61ba03d05 |
| 4.15 | 6.12.94 | 79235c8add5d |
| 4.15 | 6.18.36 | 46da5c3ea011 |
| 4.15 | 7.0.13 | 07cd2787cdf8 |
| 4.15 | 7.1 | a504b9f2797b |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4671-1 | 2026-07-05 | bullseye 6.1.176-1~deb11u1 | tracker |
| DLA-4665-1 | 2026-07-03 | bookworm 6.1.176-1 | 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:AAttack vector, adjacent network
- The vulnerable parser handles XDomain control packets from a directly connected Thunderbolt/USB4 peer on the same local fabric, not from a routable network. A malicious connected host, dock, or in-line device can send the malformed request packets.
- AC:LAttack complexity, low
- The attacker controls the packet type, declared length, checksum, and payload size, and the generic header check accepts packets shorter than the later protocol-specific struct accesses. No race or condition outside attacker control is required once an XDomain peer is connected.
- PR:NPrivileges required, none
- No target-system account or kernel capability is required; the packet is accepted from the external XDomain peer before any user credential check. XDomain must be enabled/allowed, but that is a platform configuration gate rather than attacker privilege.
- UI:NUser interaction, none
- After the malicious peer is connected, exploitation is driven entirely by packets sent over the Thunderbolt/USB4 control channel. No victim action such as opening a file or authorizing a user operation is required for the vulnerable parsing path.
- S:UScope, unchanged
- The impact is within the host kernel that processes the malformed XDomain packet. This is not a VM escape, IOMMU bypass, or cross-authority scope change.
- C:HConfidentiality impact, high
- Short PROPERTIES_REQUEST packets cause reads past the kmemdup-allocated packet into adjacent kernel heap data, including UUID/offset fields used by the response logic. Under the required higher-severity rule for out-of-bounds reads, this is high confidentiality impact.
- I:NIntegrity impact, none
- The fixed bug is an out-of-bounds read before type-specific casts, not an out-of-bounds write or direct overwrite primitive. The affected paths may use the read value for response/link-state handling, but they do not provide attacker-controlled kernel memory modification.
- A:HAvailability impact, high
- The malformed packet can drive kernel out-of-bounds heap reads from the control-channel workqueue and can be sent repeatedly by the peer. Such reads can fault or trigger kernel hardening/KASAN failures, so availability impact is high.