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CVE-2026-80745
regulator: fp9931: Fix VPOS/VNEG voltage selector table
Published 2026-09-03 (2 months ago) by the Linux kernel CNA. Subsystem drivers/regulator. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-80745 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 | not affected | 6.1.190-1 | Nothing to do. bookworm never shipped the vulnerable code. |
| Debian 13trixie | not affected | 6.12.113-1 | Nothing to do. trixie never shipped the vulnerable code. |
| Debian 14forky | fixed | 7.1.10-1 | Update the kernel and reboot. Fixed in 7.1.10-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.10-1 | Update the kernel and reboot. Fixed in 7.1.10-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
The VPOSNEG_table[] mapping does not match the FP9931 datasheet. The datasheet defines the VPOS/VNEG voltage mapping as: 00h-04h -> 7.04V (-7.04V) 05h -> 7.26V (-7.26V) 06h -> 7.49V (-7.49V) ... 28h-3Fh -> 15.06V (-15.06V) However, VPOSNEG_table[] has two issues: 1. Selector 0x00~0x04 should all map to 7.04V (5 entries), but the table has 6 entries of 7.04V, causing all subsequent entries to be shifted by one position. 2. Selectors 0x29~0x3F should all clamp to 15.06V (23 entries), but the table has only 41 entries. Any selector value above 0x28 would result in an out-of-bounds table access. Fix both issues by removing the duplicate 7.04V entry and appending the missing 23 clamped 15.06V entries, bringing the table to the correct size of 64 entries (0x00~0x3F).
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/regulator/fp9931.c
- What this is
- VOLTAGE AND CURRENT REGULATOR FRAMEWORKMAINTAINERS section matched on drivers/regulator/ · linux-kernel@vger.kernel.org · Supported
Check it on the machine
grep -wE 'CONFIG_REGULATOR|CONFIG_REGULATOR_FP9931' /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.
Show whether Debian builds this, per release
Debian does not build this code in 2 releases. The build rule could not be established for 2 releases, so nothing is claimed about those.
- bookworm, trixie?
- forky, sidn
- ?
- not established - no Makefile entry for the affected file
- n
- not enabled on any flavour - this release does not build the code
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.
- Build switches
- CONFIG_REGULATOR, CONFIG_REGULATOR_FP9931
- 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
- 2026-09-03 (2 months ago)source
- CVSS
- 8.4 high
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.18%, higher than 7.0% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- Subsystem
- drivers/regulator
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.19 | 7.1.10 | 92a959405383 |
| 6.19 | 7.2 | 66694b5f90f3 |
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 flaw is in the FP9931/JD9930 I2C EPD PMIC driver reached only via local regulator core paths (regulator_set_voltage, get_voltage_sel, map_voltage_ascend/list_voltage_table) during probe and display power management; there is no network, Bluetooth, or physical-bus attack surface to this code.
- AC:LAttack complexity, low
- On affected e-reader hardware the undersized VPOSNEG_table (41 vs 64 hardware selectors with vsel_mask 0x3F) makes selector values above 0x28 deterministically index past the table whenever map_voltage or list_voltage processes those selectors; no race or attacker-uncontrollable memory layout is required.
- PR:NPrivileges required, none
- Regulator constraint application during fp9931_probe and automatic EPD/display regulator enable paths run at boot and during normal framebuffer updates without authentication; no CAP_SYS_ADMIN, init-namespace root, or special capability is checked before reaching the vulnerable voltage-mapping code.
- UI:NUser interaction, none
- Once the FP9931 PMIC is present, voltage selection is driven by kernel probe and display refresh without requiring a victim to mount a filesystem, click a link, or perform any cooperative action beyond normal device operation.
- S:UScope, unchanged
- Impact is confined to kernel memory reads and PMIC voltage programming within the host kernel security boundary on embedded e-reader platforms; this is not a VM escape, IOMMU bypass, or cross-container authority change.
- C:HConfidentiality impact, high
- Out-of-bounds indexing of VPOSNEG_table[] in regulator_list_voltage_table reads adjacent kernel .rodata beyond the 41-entry array when selectors 0x29-0x3F are processed; out-of-bounds kernel reads are rated High per CVSS kernel guidance.
- I:HIntegrity impact, high
- The shifted voltage table causes regulator_map_voltage_ascend to select wrong VPOS/VNEG selectors written to PMIC registers (up to ±15.06V rails), and OOB table reads can return attacker-influencing values used for subsequent voltage programming, enabling incorrect high-voltage output.
- A:HAvailability impact, high
- Out-of-bounds table access in kernel context can trigger oops or panic on misaligned rodata boundaries, and programming incorrect ±15V EPD rail voltages can hang, reset, or permanently damage display power hardware, matching High availability impact guidance.