CVE-2026-53307: Linux Kernel Buffer Overflow Vulnerability

CVE-2026-53307 Overview

CVE-2026-53307 is an input validation vulnerability in the Linux kernel's pinctrl subsystem. The flaw exists in the pinconf_generic_parse_dt_pinmux() function within pinconf-generic. The function assumes the pinmux device tree property contains data when present. An empty pinmux property causes the allocator to return a special sentinel value rather than NULL. Subsequent memory accesses against that invalid pointer trigger a kernel crash. Maintainers resolved the issue by fully validating the pinmux property, including its length, before use.

Critical Impact
A malformed device tree entry can crash the Linux kernel through an invalid pointer dereference in the pin controller parsing path.

Affected Products

Linux kernel versions containing pinconf_generic_parse_dt_pinmux() prior to the referenced stable patches
Distributions shipping vulnerable stable kernel branches
Embedded and ARM-based systems relying on device tree pinmux properties

Discovery Timeline

2026-06-26 - CVE-2026-53307 published to NVD
2026-06-30 - Last updated in NVD database

Technical Details for CVE-2026-53307

Vulnerability Analysis

The defect resides in the generic pin configuration parser used by the Linux kernel pinctrl framework. The parser reads the pinmux device tree property to determine pin multiplexing configuration. The function pinconf_generic_parse_dt_pinmux() assumed the property, when present, always contained at least one value.

When the property is empty, the underlying allocator returns a non-NULL sentinel pointer instead of a valid buffer. The parser did not verify the returned pointer or the property length. Dereferencing that pointer during parsing causes a kernel oops or panic, resulting in denial of service on the affected system.

Root Cause

The root cause is missing input validation on device tree data. The routine checked for the property's presence but not its length. Empty properties produced allocator behavior the caller did not anticipate. This is a classic improper input validation defect within kernel-mode parsing code that trusts firmware-supplied data.

Attack Vector

Exploitation requires the ability to supply a crafted device tree containing an empty pinmux property. This is typically limited to actors who can modify firmware, bootloader artifacts, or overlay files loaded at boot. Successful triggering produces a kernel crash and denial of service. No public exploit or in-the-wild activity is reported for this issue.

The vulnerability manifests during device tree parsing at pin controller initialization. See the Kernel Patch Commit c98324e for the corrective validation logic.

Detection Methods for CVE-2026-53307

Indicators of Compromise

Unexpected kernel oops or panic messages referencing pinconf_generic_parse_dt_pinmux in dmesg or journalctl -k output
Boot failures on systems following device tree overlay changes
Repeated crash-loops during early boot on ARM or embedded platforms

Detection Strategies

Audit installed kernel versions against the fixed commits 6476aac1, b7842b72, and c98324ea published on kernel.org
Review device tree source and overlays for pinmux properties that are declared but empty
Monitor kernel crash telemetry for stack traces originating in the pinctrl subsystem

Monitoring Recommendations

Ingest kernel logs into a centralized logging pipeline and alert on pinctrl fault signatures
Track kernel package versions across the fleet to confirm patch adoption
Include boot-time crash detection in host health checks for embedded fleets

How to Mitigate CVE-2026-53307

Immediate Actions Required

Apply the upstream stable patches referenced by commits 6476aac1, b7842b72, and c98324ea
Update to a distribution kernel that incorporates the fix once available
Validate device tree sources under configuration management to reject empty pinmux properties

Patch Information

The fix adds full validation of the pinmux property, including its length, before dereferencing the returned buffer. Reference patches are available at Kernel Patch Commit 6476aa, Kernel Patch Commit b7842b, and Kernel Patch Commit c98324e. Rebuild and deploy kernels containing these commits across affected systems.

Workarounds

Remove or correct empty pinmux properties in device tree source and overlays
Restrict who can supply device tree blobs or overlays to trusted build pipelines
Enable Secure Boot and signed bootloader chains to prevent unauthorized device tree modification

bash

# Verify running kernel version and check for the fix
uname -r
# Confirm the patch is present in the source tree
git log --oneline drivers/pinctrl/pinconf-generic.c | grep -E '6476aac|b7842b7|c98324e'