CVE-2026-77974: Authentication Bypass Vulnerability

CVE-2026-77974 Overview

CVE-2026-77974 is a missing authentication vulnerability [CWE-306] affecting a device firmware update workflow. An attacker on an adjacent network can spoof a legitimate device and, after obtaining a single user confirmation, cause the companion application to transmit firmware over an unauthenticated and unsigned update channel. The lack of firmware signing and channel authentication allows delivery of attacker-controlled firmware to the impersonated device class.

Critical Impact
A successful attack results in delivery of unsigned firmware to a spoofed device, undermining the integrity of the device and any downstream systems that trust it.

Affected Products

Affected vendor: Not Available in NVD data
Affected product: Not Available in NVD data
Affected versions: Not Available in NVD data

Discovery Timeline

2026-09-09 - CVE-2026-77974 published to NVD
2026-09-09 - Last updated in NVD database

Technical Details for CVE-2026-77974

Vulnerability Analysis

The flaw resides in the firmware update path used by a companion application to push firmware to a paired device. The update channel does not authenticate the device endpoint and does not verify a cryptographic signature on the firmware image. As a result, an attacker who can impersonate the device on an adjacent network can receive firmware intended for the legitimate device, or push an unsigned image if the same channel is used bidirectionally.

User interaction is required. The victim must approve a single confirmation prompt in the application to initiate the transfer. Because the channel lacks integrity controls, once the confirmation is granted the application transmits firmware without further validation of the receiving party.

Root Cause

The root cause is missing authentication for a critical function [CWE-306]. The firmware update process trusts the device identity presented on the local link and does not enforce signature verification on the transmitted firmware. Both controls are required to establish trust in an over-the-air update pipeline.

Attack Vector

Exploitation requires adjacent network access, meaning the attacker must be within radio or local network range of the target. The attacker spoofs the identity of a legitimate device and induces the user to approve the firmware transfer prompt. See the CISA Vulnerability Assessment Report for the coordinated assessment details.

No verified public proof-of-concept code is available. The vulnerability mechanism is described in prose because no sanitized exploitation code has been published by the coordinating authority.

Detection Methods for CVE-2026-77974

Indicators of Compromise

Unexpected firmware update prompts appearing in the companion application without a corresponding user-initiated action.
Duplicate device advertisements on the adjacent network segment, indicating a spoofed peer.
Firmware version strings on devices that do not match any officially released image hash from the vendor.

Detection Strategies

Monitor pairing and discovery traffic on adjacent networks for two endpoints advertising the same device identifier.
Compare firmware image hashes on managed devices against a known-good vendor manifest after each update event.
Alert on firmware update transactions that complete without a preceding signed manifest exchange.

Monitoring Recommendations

Log every firmware update confirmation event from the companion application, including timestamp, user, and device identifier.
Capture wireless or local link telemetry in environments that host affected device classes to enable retrospective analysis.
Correlate update events with vendor release calendars to flag out-of-band firmware transfers.

How to Mitigate CVE-2026-77974

Immediate Actions Required

Instruct users to deny firmware update prompts that were not explicitly initiated from a trusted administrator workflow.
Restrict use of affected devices to trusted radio and network environments until a patched application or firmware is available.
Inventory all deployed devices and their current firmware versions to establish a baseline for post-patch verification.

Patch Information

No vendor patch information is published in the referenced NVD entry or the associated CISA Vulnerability Assessment Report. Monitor the coordinating authority and the device vendor for a security update that introduces authenticated pairing and signed firmware images.

Workarounds

Perform firmware updates only in physically controlled environments where adjacent-network spoofing is not feasible.
Require out-of-band verification of firmware image hashes before approving any update confirmation in the application.
Disable automatic pairing features in the companion application when they are not required for daily operation.

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# Configuration example not available - refer to vendor documentation once a patch is released