CVE-2026-53297: Linux Kernel Privilege Escalation Flaw

CVE-2026-53297 Overview

CVE-2026-53297 is a null pointer dereference vulnerability in the Linux kernel's Microsoft Azure Network Adapter (MANA) network driver. The flaw exists in the mana_remove() function, which fails to guard against double invocation during power management (PM) resume failure paths. When mana_attach() returns an error during resume, mana_probe() calls mana_remove(), which nullifies gd->gdma_context and gd->driver_data. A subsequent driver unbind triggers mana_remove() a second time, dereferencing a NULL gc pointer and causing a kernel panic.

Critical Impact
A local trigger during PM resume failure can cause a kernel panic through NULL pointer dereference, resulting in denial of service on affected systems running the MANA network driver.

Affected Products

Linux kernel with the net/mana driver enabled
Microsoft Azure Network Adapter (MANA) driver in vulnerable kernel versions
Systems using MANA networking with power management resume paths

Discovery Timeline

2026-06-26 - CVE-2026-53297 published to NVD
2026-06-30 - Last updated in NVD database

Technical Details for CVE-2026-53297

Vulnerability Analysis

The vulnerability resides in the MANA driver's device teardown logic. When PM resume fails during mana_probe(), the recovery path invokes mana_remove() to tear down partially initialized state. This teardown sets gd->gdma_context and gd->driver_data to NULL. However, a failed resume callback does not automatically unbind the driver from the device.

When the device is later unbound, the kernel calls mana_remove() again. The function assigns dev = gc->dev before validating that gc (the gdma context) is non-NULL. Because the prior invocation already cleared the context pointer, this second call dereferences a NULL pointer and triggers a kernel panic.

This is a classic double-invocation flaw in device driver cleanup paths, categorized as a NULL pointer dereference [CWE-476]. Similar patterns have historically appeared across Linux subsystems where teardown functions assume single-execution semantics.

Root Cause

The root cause is missing idempotency in mana_remove(). The function assumes it will be called exactly once but does not enforce this contract. The dev = gc->dev assignment occurs before any NULL validation, so the second invocation dereferences a stale/cleared pointer.

Attack Vector

Triggering the flaw requires a PM resume failure followed by a driver unbind on a system using the MANA driver. This is primarily a reliability and denial-of-service issue rather than a remote exploitation vector. The condition typically arises on Azure virtual machines or systems using MANA where suspend/resume cycles encounter attach failures.

The vulnerability manifests during kernel driver lifecycle transitions. See the upstream commit references for the specific code paths and fix implementation.

Detection Methods for CVE-2026-53297

Indicators of Compromise

Kernel panic messages referencing mana_remove in the call stack
Oops or BUG reports containing NULL pointer dereference at gc->dev access
System crashes correlated with PM suspend/resume cycles on MANA-equipped hosts
Repeated driver unbind operations following failed resume events in kernel logs

Detection Strategies

Inventory kernel versions across Linux fleets and compare against patched stable kernel releases containing commits 50271d7ec951, a1ddfd2c0b7a, and bbe5c3c57064.
Monitor dmesg and journalctl -k output for panic signatures involving the MANA driver during resume operations.
Review Azure VM host telemetry for unexpected reboots or guest crashes coinciding with maintenance events that involve suspend/resume.

Monitoring Recommendations

Forward kernel logs to a centralized logging platform and alert on mana_remove stack traces.
Track PM resume failures using systemd suspend/resume event logs and correlate with subsequent driver rebind attempts.
Establish baseline crash telemetry to identify anomalous panic rates on MANA-enabled systems.

How to Mitigate CVE-2026-53297

Immediate Actions Required

Apply the upstream Linux kernel patches that add the NULL guard to mana_remove() before executing device teardown logic.
Update to a stable kernel release that incorporates the fix commits published on git.kernel.org.
Avoid unnecessary suspend/resume cycles on production MANA-enabled hosts until patched kernels are deployed.

Patch Information

The fix adds an early return in mana_remove() when gdma_context or driver_data is NULL, making the second invocation harmless. The dev = gc->dev assignment is moved after the NULL guard so it cannot dereference a NULL pointer. The upstream commits are available at kernel.org commit 50271d7e, kernel.org commit a1ddfd2c, and kernel.org commit bbe5c3c5.

Workarounds

Where patching is not immediately feasible, disable suspend/resume operations on affected hosts to avoid triggering the failure path.
Blacklist the MANA driver on systems where it is not required, then reload only after applying patched kernels.
Coordinate with cloud provider maintenance schedules to reduce exposure to PM resume events on Azure guests.

bash

# Verify running kernel version and check for MANA driver presence
uname -r
lsmod | grep mana

# Review recent kernel messages for MANA-related panics
dmesg | grep -i mana
journalctl -k --since "7 days ago" | grep -i "mana_remove\|null pointer"