CVE-2025-1051: Sonos Era 300 Firmware RCE Vulnerability

CVE-2025-1051 Overview

CVE-2025-1051 is a heap-based buffer overflow in the Sonos Era 300 smart speaker firmware that enables remote code execution. The flaw resides in the speaker's handling of Apple Lossless Audio Codec (ALAC) data and stems from missing validation of user-supplied data length before copying it into a heap buffer. Network-adjacent attackers can exploit the issue without authentication, executing arbitrary code as the anacapa user. The Zero Day Initiative tracked the issue as ZDI-CAN-25865 and assigned advisory ZDI-25-311. Affected firmware version 81.1-58074 is identified in the published CPE data.

Critical Impact
Unauthenticated attackers on the same network segment can execute arbitrary code on Sonos Era 300 speakers by sending malformed ALAC audio data, gaining a foothold on the device as the anacapa user.

Affected Products

Sonos Era 300 speaker hardware
Sonos Era 300 firmware version 81.1-58074
Deployments exposing the speaker to untrusted Wi-Fi or LAN segments

Discovery Timeline

2025-06-02 - CVE-2025-1051 published to the National Vulnerability Database
2026-06-17 - Last updated in the NVD database

Technical Details for CVE-2025-1051

Vulnerability Analysis

The vulnerability resides in the ALAC parser used by the Sonos Era 300 firmware. ALAC is an Apple-developed lossless audio format that the speaker decodes when streaming compatible media. The parser copies user-controlled data into a fixed-size heap buffer without first verifying the supplied length.

An attacker on an adjacent network can craft an ALAC stream whose internal length fields exceed the destination buffer. When the firmware copies the oversized payload, it corrupts adjacent heap metadata and allocator structures. Successful exploitation yields code execution in the context of the anacapa user, the runtime account used by Sonos services on the device.

The weakness is classified as [CWE-122] Heap-based Buffer Overflow and [CWE-787] Out-of-bounds Write. No authentication is required, and no user interaction on the speaker is needed to trigger the parser.

Root Cause

The ALAC processing routine fails to validate the length of attacker-controlled audio frame data before invoking a memory copy into a heap-allocated buffer. The firmware trusts size fields embedded in the audio container and copies bytes directly, allowing a write beyond the buffer's allocated size.

Attack Vector

Exploitation requires adjacent network access, such as the same Wi-Fi network or LAN as the targeted speaker. An attacker delivers a malicious ALAC payload to the speaker's audio processing service. Because the device exposes media handling without authentication, any peer on the network segment can reach the vulnerable code path. Refer to the Zero Day Initiative Advisory ZDI-25-311 for additional technical context.

Detection Methods for CVE-2025-1051

Indicators of Compromise

Unexpected outbound connections from a Sonos Era 300 speaker to unknown hosts after receiving streamed audio
Sonos device reboots, crashes, or service restarts coinciding with ALAC playback from untrusted sources
Unusual multicast or unicast traffic targeting Sonos media ports on the local network

Detection Strategies

Inspect network traffic for malformed ALAC frames or oversized audio container headers directed at Sonos speakers
Baseline normal Sonos device traffic patterns and alert on deviations such as new listening ports or outbound shell-like sessions
Monitor DHCP and ARP tables for unauthorized devices joining the same VLAN as Sonos hardware

Monitoring Recommendations

Forward wireless controller and switch logs to a centralized analytics platform to correlate IoT device behavior
Track firmware versions reported by Sonos speakers and alert when devices remain on vulnerable build 81.1-58074
Enable rogue device detection on Wi-Fi infrastructure to identify attackers staging on the speaker's network segment

How to Mitigate CVE-2025-1051

Immediate Actions Required

Apply the latest Sonos Era 300 firmware update through the Sonos app as soon as it is available
Isolate Sonos speakers on a dedicated VLAN or guest network separated from sensitive corporate and user devices
Disable automatic media handling from untrusted sources and restrict casting or AirPlay sources to known users
Audit Wi-Fi networks for unknown clients that could reach the speaker over adjacent network paths

Patch Information

Review the Zero Day Initiative Advisory ZDI-25-311 for vendor remediation status. Sonos typically distributes firmware updates automatically to internet-connected speakers; verify that affected devices have advanced beyond firmware 81.1-58074.

Workarounds

Segment Sonos devices behind a firewall that blocks lateral traffic from unmanaged endpoints and guest Wi-Fi clients
Disable Wi-Fi on the speaker and rely on wired Ethernet within a controlled VLAN where feasible
Restrict the network so that only trusted streaming sources can reach the speaker's audio service ports

bash

# Configuration example
# Example: isolate Sonos speakers on a dedicated IoT VLAN (vendor-neutral switch syntax)
vlan 50
  name IoT-Sonos
interface GigabitEthernet0/10
  description Sonos Era 300
  switchport mode access
  switchport access vlan 50
# Block lateral traffic from IoT VLAN to user and server VLANs
ip access-list extended IOT-ISOLATION
  deny ip 10.50.0.0 0.0.255.255 10.0.0.0 0.255.255.255
  permit ip 10.50.0.0 0.0.255.255 any