CVE-2025-1050: Sonos S2 Era 300 RCE Vulnerability

CVE-2025-1050 Overview

CVE-2025-1050 is an out-of-bounds write vulnerability [CWE-787] affecting Sonos Era 300 speakers running the Sonos S2 software. The flaw resides in the processing of HTTP Live Streaming (HLS) playlist data and stems from insufficient validation of user-supplied input. Network-adjacent attackers can exploit this vulnerability without authentication to achieve remote code execution in the context of the anacapa user. The issue was reported through the Zero Day Initiative (ZDI) as ZDI-CAN-25606 and tracked publicly as ZDI-25-225.

Critical Impact
Unauthenticated attackers on an adjacent network can execute arbitrary code on Sonos Era 300 speakers by delivering malicious HLS playlist data, compromising the device's integrity, confidentiality, and availability.

Affected Products

Sonos Era 300 speakers
Sonos S2 software
Devices exposing HLS playlist processing on adjacent networks

Discovery Timeline

2025-04-23 - CVE-2025-1050 published to the National Vulnerability Database (NVD)
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-1050

Vulnerability Analysis

The vulnerability resides in the HLS playlist parsing logic used by the Sonos S2 software stack on Era 300 speakers. HLS playlists are text-based manifests that describe media segments for streaming playback. When the speaker processes a crafted playlist, the parser writes beyond the bounds of an allocated buffer, corrupting adjacent memory.

An attacker on the same network segment can deliver a malicious playlist to the device through its streaming interfaces. No user interaction or authentication is required. Successful exploitation grants code execution as the anacapa service account, which controls audio playback and device management functions on the speaker.

See the Zero Day Initiative Advisory ZDI-25-225 for additional technical context.

Root Cause

The root cause is missing bounds validation on user-supplied data inside the HLS playlist processing routine. The code accepts attacker-controlled values from the playlist and writes them into a fixed-size data structure without verifying length or boundary conditions. This pattern is classified under [CWE-787] Out-of-Bounds Write.

Attack Vector

The attack vector is adjacent network (AV:A). The attacker must reach the speaker through the local network, Wi-Fi, or another logically adjacent broadcast domain. From that position, the attacker delivers a malformed HLS playlist that triggers the parser flaw and overwrites memory to hijack execution flow.

The vulnerability requires no public exploit code to describe.
No verified proof-of-concept has been released at the time of writing.
Refer to ZDI-25-225 for vendor-coordinated technical details.

Detection Methods for CVE-2025-1050

Indicators of Compromise

Unexpected outbound network connections originating from Sonos Era 300 devices to unknown hosts.
Anomalous HLS playlist requests containing oversized fields or malformed tags directed at Sonos speakers.
Unusual process activity or service restarts on Sonos devices indicating crash or exploitation attempts.

Detection Strategies

Inspect HTTP traffic on the local network for HLS manifests (.m3u8) with abnormally long URI fields or malformed #EXT-X- directives.
Monitor Sonos device telemetry and syslog forwarding for repeated parser errors or service restarts associated with media playback.
Use network detection and response tooling to baseline normal Sonos traffic patterns and flag deviations from streaming sources.

Monitoring Recommendations

Segment IoT devices, including Sonos speakers, onto isolated VLANs and log all traffic crossing segmentation boundaries.
Enable DNS and HTTP logging on network egress points to identify suspicious streaming endpoints contacted by speakers.
Aggregate IoT and network logs in a centralized analytics platform to correlate anomalous playback requests with adjacent host activity.

How to Mitigate CVE-2025-1050

Immediate Actions Required

Apply the latest Sonos S2 firmware update to all Era 300 speakers as soon as the vendor patch is available.
Restrict network access to Sonos devices by placing them on a dedicated VLAN with strict access control lists (ACLs).
Disable streaming or HLS-based services on affected speakers if they are not required in the environment.

Patch Information

Sonos addresses this issue through Sonos S2 software updates distributed to Era 300 speakers. Administrators should verify that automatic updates are enabled and confirm that devices have received the latest firmware. Consult the Zero Day Initiative Advisory ZDI-25-225 and Sonos product release notes for fixed version details.

Workarounds

Block untrusted devices and guest networks from reaching Sonos speakers using firewall rules.
Disable Wi-Fi access for the speakers and rely on wired connections within a controlled segment where feasible.
Restrict outbound streaming sources to known, trusted services to reduce exposure to malicious HLS playlists.

bash

# Example firewall rule to isolate Sonos devices on a dedicated VLAN
iptables -A FORWARD -s 192.168.50.0/24 -d <sonos_vlan_subnet> -j DROP
iptables -A FORWARD -s <sonos_vlan_subnet> -d 192.168.50.0/24 -j DROP