tty: serial: 8250: protect against NULL uart->port.dev in register (CVE-2026-97480) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-97480

tty: serial: 8250: protect against NULL uart->port.dev in register

Answer in brief

CVE-2026-97480 records a Unknown severity vulnerability in tty: serial: 8250: protect against NULL uart->port.dev in register. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 24, 2026Updated Sep 24, 2026Source checked Sep 25, 2026First seen by HOL Sep 25, 2026Material review Sep 24, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5cbab666721d974bfe033a12045d808936deaefd \|\| >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <941c9f84c9b6310f7aaa1c8c785dcc634ee33050 \|\| >=0 <6.18.53	5cbab666721d974bfe033a12045d808936deaefd, 941c9f84c9b6310f7aaa1c8c785dcc634ee33050, 6.18.53

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux.
Review the reported fix. Update Linux/Linux to 5cbab666721d974bfe033a12045d808936deaefd if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 24, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 24, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 25, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: tty: serial: 8250: protect against NULL uart->port.dev in register serial8250_register_8250_port() conditionally copies uart->port.dev from up->port.dev only when up->port.dev is non-NULL: if (up->port.dev) { uart->port.dev = up->port.dev; ... } So if both the existing uart slot and up have a NULL ->dev, uart->port.dev remains NULL. The very next ACPI companion check then dereferences it unconditionally: if (!has_acpi_companion(uart->port.dev)) { has_acpi_companion() reads dev->fwnode without a NULL guard (include/linux/acpi.h), so this NULL-derefs the kernel for the remaining no-dev case rather than just skipping the mctrl_gpio_init() initialisation as intended. smatch flags the inconsistency: drivers/tty/serial/8250/8250_core.c:767 serial8250_register_8250_port() error: 'uart->port.dev' could be null (see line 719) Guard the call with a NULL check so register continues to work for callers that legitimately have no parent device (legacy non-OF/non-ACPI registrations). No functional change for callers that pass a non-NULL ->dev.

Quoted source text, attributed separately from HOL analysis.