CVE-2025-52290: 
Ffmpeg vulnerability analysis and mitigation

CVE-2025-52290 is a NULL pointer dereference vulnerability in FFmpeg's avpriv_h264_has_num_reorder_frames function that allows unauthenticated attackers to cause a Denial of Service (DoS) by supplying a specially crafted media file. The vulnerability was disclosed on October 19, 2026, and affects FFmpeg version N-119856-gbe46370941. It carries a CVSS v3.1 base score of 7.5 (High) (GitHub Advisory, Red Hat Bugzilla).

The root cause is a NULL pointer dereference (CWE-476) combined with uncontrolled resource consumption (CWE-400) in the avpriv_h264_has_num_reorder_frames function within FFmpeg's H.264 decoding logic. An attacker can trigger the flaw by providing a malformed or crafted media file for processing — no authentication or user interaction is required, and the attack can be delivered over the network. When the vulnerable function attempts to dereference a pointer that has not been properly validated, the process crashes, resulting in a DoS condition (GitHub Advisory, Red Hat Bugzilla). A public discussion of the issue was noted on Infosec.exchange and the oss-security mailing list (GitHub Advisory).

Successful exploitation causes the FFmpeg process to crash, resulting in a complete loss of availability for any service or application relying on FFmpeg for media processing. There is no impact on confidentiality or data integrity — the vulnerability is limited to availability (DoS). Applications such as media transcoding pipelines, streaming servers, or video processing platforms that automatically ingest user-supplied media files are at elevated risk of service disruption (GitHub Advisory, Red Hat Bugzilla).

There is no public proof-of-concept exploit code and no evidence of in-the-wild exploitation at this time (GitHub Advisory). The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. The EPSS score is approximately 0.42%, placing it in the 35th percentile for exploitation likelihood within 30 days. However, the attack requires no privileges and no user interaction, making it automatable if a PoC were to emerge (GitHub Advisory).

1. Identify target: Locate a service or application that uses FFmpeg version N-119856-gbe46370941 for media processing, such as a video transcoding API, streaming platform, or media upload endpoint.
2. Craft malicious media file: Create a specially malformed media file (e.g., an H.264-encoded video) designed to trigger a NULL pointer dereference in the avpriv_h264_has_num_reorder_frames function during parsing.
3. Submit the file: Upload or submit the crafted file to the target service — for example, via a file upload form, API endpoint, or streaming input — causing FFmpeg to process it.
4. Trigger crash: FFmpeg attempts to process the malformed file, the avpriv_h264_has_num_reorder_frames function dereferences a NULL pointer, and the FFmpeg process crashes, causing a DoS for the affected service (GitHub Advisory).

• Logs: Sudden FFmpeg process termination logs (segmentation fault / SIGSEGV) coinciding with media file processing events; application error logs referencing crashes in H.264 decoding routines.
• Process: Unexpected FFmpeg process crashes or restarts, particularly when processing externally supplied media files.
• File System: Presence of unusual or malformed media files (e.g., H.264 video files with anomalous headers or truncated structures) in upload or processing directories.
• Network: Repeated submission of media files from the same source IP that consistently trigger FFmpeg crashes, potentially indicating automated probing (GitHub Advisory).

A patch is available via the GitHub Security Advisory (GHSA-wv9f-x489-g252); users should update FFmpeg beyond the affected version N-119856-gbe46370941 as soon as a fixed release is available (GitHub Advisory). As interim mitigations, implement input validation to reject malformed or unexpected media files before they reach FFmpeg, restrict media file processing to trusted sources only, and run FFmpeg in a sandboxed or containerized environment to limit the blast radius of a crash. Rate-limiting or queuing media processing requests can also reduce the risk of sustained DoS (Red Hat Bugzilla).

The vulnerability was discussed on the Infosec.exchange Mastodon instance shortly after disclosure, and was reported to the oss-security mailing list on October 20, 2026. Red Hat opened a tracking bug (Bug 2555742) and assigned it medium priority/severity. No major vendor statements or widespread media coverage have been observed beyond standard vulnerability database entries (GitHub Advisory, Red Hat Bugzilla).