CVE-2021-46980

usb: typec: ucsi: Retrieve all the PDOs instead of just the first 4

Published Feb 28, 2024 CVSS 3.1 · 7.1 High EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

usb: typec: ucsi: Retrieve all the PDOs instead of just the first 4

commit 4dbc6a4ef06d ("usb: typec: ucsi: save power data objects
in PD mode") introduced retrieval of the PDOs when connected to a
PD-capable source. But only the first 4 PDOs are received since
that is the maximum number that can be fetched at a time given the
MESSAGE_IN length limitation (16 bytes). However, as per the PD spec
a connected source may advertise up to a maximum of 7 PDOs.

If such a source is connected it's possible the PPM could have
negotiated a power contract with one of the PDOs at index greater
than 4, and would be reflected in the request data object's (RDO)
object position field. This would result in an out-of-bounds access
when the rdo_index() is used to index into the src_pdos array in
ucsi_psy_get_voltage_now().

With the help of the UBSAN -fsanitize=array-bounds checker enabled
this exact issue is revealed when connecting to a PD source adapter
that advertise 5 PDOs and the PPM enters a contract having selected
the 5th one.

[ 151.545106][ T70] Unexpected kernel BRK exception at EL1
[ 151.545112][ T70] Internal error: BRK handler: f2005512 [#1] PREEMPT SMP
...
[ 151.545499][ T70] pc : ucsi_psy_get_prop+0x208/0x20c
[ 151.545507][ T70] lr : power_supply_show_property+0xc0/0x328
...
[ 151.545542][ T70] Call trace:
[ 151.545544][ T70] ucsi_psy_get_prop+0x208/0x20c
[ 151.545546][ T70] power_supply_uevent+0x1a4/0x2f0
[ 151.545550][ T70] dev_uevent+0x200/0x384
[ 151.545555][ T70] kobject_uevent_env+0x1d4/0x7e8
[ 151.545557][ T70] power_supply_changed_work+0x174/0x31c
[ 151.545562][ T70] process_one_work+0x244/0x6f0
[ 151.545564][ T70] worker_thread+0x3e0/0xa64

We can resolve this by instead retrieving and storing up to the
maximum of 7 PDOs in the con->src_pdos array. This would involve
two calls to the GET_PDOS command.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
Metrics cvssV3_1

{'score': 6.0, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H'}

cvssV3_1

{'score': 7.1, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H'}

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
May 11, 2026, 1:45 PM
Reserved
Feb 27, 2024, 6:42 PM
Status
Analyzed
Published
Feb 28, 2024, 9:15 AM
Modified
Jun 17, 2026, 4:16 AM
Severity
Low
Public date
Feb 28, 2024, 12:00 AM