CVE-2026-89172: Microchip Side Channel Vulnerability

CVE-2026-89172 Overview

CVE-2026-89172 is a physical side-channel vulnerability affecting Microchip cryptographic reference implementations distributed in Application Notes AN1044 and AN953, and Development Tool SW300052. The flaw is tracked under CWE-1300: Improper Protection of Physical Side Channels. An attacker with physical access to a device running the affected cryptographic routines can observe emanations such as timing, power consumption, or electromagnetic signals to recover secret key material. Microchip has documented the issue in its Security Vulnerability Reporting Guide.

Critical Impact
An attacker with physical proximity to an embedded device using the affected Microchip cryptographic implementations can extract confidential key material through side-channel analysis, undermining the confidentiality of protected data and downstream systems.

Affected Products

Microchip Application Note AN1044 through revision A
Microchip Application Note AN953 through revision A
Microchip Development Tool SW300052 through version 2.6

Discovery Timeline

2026-09-12 - CVE-2026-89172 published to NVD
2026-09-16 - Last updated in NVD database

Technical Details for CVE-2026-89172

Vulnerability Analysis

The affected Microchip artifacts provide reference cryptographic algorithm implementations intended for use on embedded microcontrollers. These implementations do not incorporate countermeasures against physical side-channel analysis. Sensitive operations execute in ways that leak information about secret inputs through measurable physical characteristics of the device.

An adversary in physical possession of a target device can capture power traces, electromagnetic emissions, or precise timing of cryptographic operations. Statistical techniques such as Differential Power Analysis (DPA) or Correlation Power Analysis (CPA) then correlate those measurements with candidate key hypotheses to recover secret keys.

The scope of impact extends beyond the local device. Recovered keys can be reused to decrypt intercepted traffic, forge signatures, or impersonate the device in a larger system, which is reflected in the CVSS subsequent-system confidentiality impact.

Root Cause

The root cause is the absence of side-channel countermeasures in the reference cryptographic code, categorized under CWE-1300. Standard textbook algorithm implementations execute with data-dependent instruction paths, memory accesses, and power draw. Without masking, hiding, constant-time execution, or algorithmic blinding, the physical behavior of the device reveals intermediate values tied to the secret key.

Attack Vector

Exploitation requires physical access and specialized equipment such as an oscilloscope, current probe, or electromagnetic near-field probe. The attacker triggers repeated cryptographic operations on the target device and captures physical measurements synchronized with those operations. Analysis is performed offline against the collected traces to recover the key. High attack complexity reflects the expertise, equipment, and trace volume typically required.

No public proof-of-concept for CVE-2026-89172 is currently listed in the referenced advisories. Readers should consult the Microchip advisory for authoritative technical detail.

Detection Methods for CVE-2026-89172

Indicators of Compromise

Successful side-channel key extraction leaves no reliable software-visible artifact on the target microcontroller, so traditional endpoint indicators do not apply.
Signs of physical tampering, decapsulation, probe attachment, or removal of devices from field deployments may indicate an attempted attack.
Downstream anomalies such as unexpected use of device certificates or keys in authentication logs can signal that extracted material is being reused.

Detection Strategies

Inventory all firmware images and embedded designs that incorporate code derived from AN1044, AN953, or SW300052 versions through the affected revisions.
Perform side-channel evaluation of production devices using DPA or CPA test benches to confirm whether deployed implementations leak.
Monitor backend systems that trust device-held keys for signs of key reuse from unexpected locations or at unexpected volumes.

Monitoring Recommendations

Log and alert on authentication or signing events from device identities that occur outside expected operational windows or geographies.
Track physical custody of high-value devices, including field returns and RMA units, and treat units with broken custody as potentially compromised.
Review supply-chain and manufacturing-line access controls for locations where affected devices are provisioned with secrets.

How to Mitigate CVE-2026-89172

Immediate Actions Required

Identify products that ship the vulnerable Microchip reference code and classify them by exposure to physical access.
Replace the affected cryptographic routines with side-channel resistant implementations, such as vendor-supplied hardened libraries or hardware cryptographic accelerators on the target microcontroller.
Plan key rotation for any device whose private keys may have been exposed to untrusted physical environments.

Patch Information

Microchip tracks this issue in its Security Vulnerability Reporting Guide. The affected artifacts are reference materials rather than deployed binaries, so remediation typically requires updating derived firmware. Consult Microchip directly for updated application notes and library versions that supersede AN1044 revision A, AN953 revision A, and SW300052 version 2.6.

Workarounds

Move cryptographic operations to a hardware security element or secure enclave that provides certified side-channel resistance.
Restrict physical access to devices in the field using tamper-evident enclosures, potting compounds, and tamper switches that zeroize keys on intrusion.
Reduce the value of any single extracted key by using per-device keys, short key lifetimes, and server-side rate limiting on operations that depend on device keys.

bash

# Configuration example
# No configuration-level mitigation exists for CVE-2026-89172.
# Remediation requires replacing the vulnerable cryptographic
# implementation in firmware. Refer to the Microchip advisory
# for updated reference code and hardened library guidance.