CVE-2025-47808 Overview
CVE-2025-47808 is a NULL pointer dereference vulnerability in the GStreamer multimedia framework through version 1.26.1. The flaw resides in the tmplayer_parse_line function of the subparse plugin. Parsing a malformed TMPlayer subtitle file triggers a NULL pointer dereference and crashes the host process [CWE-476]. Because GStreamer is embedded in numerous media players, browsers, and desktop environments across Linux distributions, a crafted subtitle file delivered over the network can produce a denial-of-service condition on any application that opens it.
Critical Impact
A crafted subtitle file parsed by the GStreamer subparse plugin crashes the consuming application, resulting in denial of service for media playback and any embedding process.
Affected Products
- GStreamer versions up to and including 1.26.1
- Applications and desktop environments that link the GStreamer subparse plugin
- Linux distributions shipping vulnerable GStreamer packages
Discovery Timeline
- 2025-08-07 - CVE-2025-47808 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-47808
Vulnerability Analysis
The defect exists in the tmplayer_parse_line function inside the GStreamer subparse plugin, which handles TMPlayer-format subtitle files. During parsing of a malformed subtitle line, the function dereferences a pointer that has not been validated against NULL. The result is a segmentation fault in the process hosting the GStreamer pipeline. GStreamer is invoked automatically by many media applications when a subtitle file is loaded alongside a media asset, so the parsing path is reachable without additional user interaction beyond opening the media. The vulnerability produces a crash rather than memory corruption, limiting impact to availability. See the GitHub Security Advisory ATREDIS-2025-0003 for the reported technical details.
Root Cause
The root cause is missing input validation in tmplayer_parse_line. The function assumes structural fields returned by tokenization are non-NULL and proceeds to dereference them. Certain malformed TMPlayer inputs cause tokenization to return a NULL pointer, which is then read directly, triggering the crash.
Attack Vector
An attacker distributes a crafted TMPlayer subtitle file, typically alongside or referenced by a media file. When a victim opens the media in an application using GStreamer, the subparse plugin loads the subtitle and the parser dereferences the NULL pointer. Delivery vectors include email attachments, web downloads, streaming metadata, and shared network storage. Exploitation requires no authentication.
No verified exploit code is available. Refer to the GStreamer Security Information page for vendor guidance.
Detection Methods for CVE-2025-47808
Indicators of Compromise
- Unexpected termination of media player processes such as totem, rhythmbox, gst-launch-1.0, or browser media components immediately after loading a subtitle file
- Core dump artifacts referencing libgstsubparse or the tmplayer_parse_line symbol
- TMPlayer-format .sub or .txt subtitle files arriving from untrusted sources
Detection Strategies
- Monitor process crash telemetry for applications linking libgstsubparse.so and correlate with recent subtitle file access
- Inspect files with TMPlayer subtitle syntax originating from untrusted email, download, or share sources
- Track installed GStreamer package versions across the fleet and flag hosts running 1.26.1 or earlier
Monitoring Recommendations
- Enable core dump collection on Linux endpoints to capture faulting stack traces containing subparse frames
- Alert on repeated crash events in media-handling processes within short time windows, which may indicate targeted delivery
- Ingest package inventory into a SIEM or data lake to continuously track GStreamer versions against the fixed release
How to Mitigate CVE-2025-47808
Immediate Actions Required
- Upgrade GStreamer to a version released after 1.26.1 that addresses the tmplayer_parse_line NULL pointer dereference
- Apply distribution security updates for GStreamer packages, including gst-plugins-base which ships the subparse plugin
- Restrict opening of subtitle files from untrusted sources until patches are deployed
Patch Information
Refer to the GStreamer Security Information page for the official fix and release notes. Distribution vendors publish corresponding package updates through their standard security channels.
Workarounds
- Remove or disable the subparse plugin where subtitle rendering is not required
- Block delivery of TMPlayer-format subtitle files (.sub, .txt matching TMPlayer syntax) at email and web gateways from untrusted senders
- Isolate media playback in sandboxed user sessions to contain crashes and limit impact on other workloads
# Identify installed GStreamer version and locate the subparse plugin on Linux
gst-inspect-1.0 --version
find / -name 'libgstsubparse.so' 2>/dev/null
# Debian/Ubuntu: update GStreamer base plugins containing subparse
sudo apt-get update && sudo apt-get install --only-upgrade \
gstreamer1.0-plugins-base libgstreamer-plugins-base1.0-0
# Fedora/RHEL: update GStreamer base plugins
sudo dnf upgrade gstreamer1-plugins-base
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
