CVE-2025-1816: FFmpeg IAMF Memory Leak Vulnerability

CVE-2025-1816 Overview

CVE-2025-1816 is a memory leak vulnerability in FFmpeg, the widely used multimedia framework for encoding, decoding, and processing audio and video files. The flaw resides in the audio_element_obu function within libavformat/iamf_parse.c, which is part of the Immersive Audio Model and Formats (IAMF) file handler. Manipulation of the num_parameters argument causes memory to be allocated but never released, leading to resource exhaustion over time. The issue is tracked under [CWE-401] (Missing Release of Memory after Effective Lifetime) and can be triggered remotely when FFmpeg processes a crafted IAMF file. A public proof-of-concept has been disclosed via the FFmpeg bug tracker.

Critical Impact
Remote attackers can trigger progressive memory exhaustion in FFmpeg-based services by supplying malformed IAMF media files, potentially degrading availability of transcoding pipelines and media processors.

Affected Products

FFmpeg up to commit 6e26f57f672b05e7b8b052007a83aef99dc81ccb
FFmpeg builds incorporating the IAMF file handler in libavformat/iamf_parse.c
Downstream applications and services that link against vulnerable FFmpeg libraries for IAMF media parsing

Discovery Timeline

2025-03-02 - CVE-2025-1816 published to the National Vulnerability Database
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-1816

Vulnerability Analysis

The vulnerability is a memory leak in FFmpeg's IAMF parser. IAMF (Immersive Audio Model and Formats) is a next-generation audio container specification, and FFmpeg parses its structures through libavformat/iamf_parse.c. The audio_element_obu function is invoked when FFmpeg encounters an Audio Element OBU (Open Bitstream Unit) inside an IAMF stream. During parsing, memory is allocated based on the num_parameters field extracted from the input. On specific error paths or with malformed input, allocated buffers are not released before the function returns, resulting in leaked heap allocations.

Because the parser processes untrusted content from network sources, streaming pipelines, or user-supplied media files, an attacker can repeatedly submit crafted IAMF payloads to grow FFmpeg's resident memory footprint. This can lead to denial-of-service conditions in long-running services such as transcoders, media gateways, and content delivery workers. The attack requires some form of user interaction to load the crafted file, consistent with the CVSS UI:P metric assigned by the reporter.

Root Cause

The root cause is missing cleanup logic on error paths within audio_element_obu. When the num_parameters counter drives buffer allocation, subsequent parse failures or validation checks return without invoking the corresponding free routines. This is the classic [CWE-401] pattern: allocated memory outlives its intended scope because the code fails to release it before returning control to the caller.

Attack Vector

Exploitation is remote and requires that a victim application processes an attacker-supplied IAMF file. Delivery channels include HTTP-hosted media, email attachments, user uploads to transcoding services, or streaming inputs. Repeated processing of the malicious payload amplifies impact, gradually exhausting available memory and degrading service performance until the FFmpeg process or its host crashes. A proof-of-concept has been published on the FFmpeg Trac ticket tracker. See the FFmpeg Ticket Discussion and the FFmpeg Ticket PoC Attachment for technical details.

Detection Methods for CVE-2025-1816

Indicators of Compromise

Sustained, unexplained memory growth in FFmpeg processes handling IAMF or unknown media formats
Repeated ingestion of IAMF files (.iamf or containers advertising Audio Element OBUs) from untrusted sources
FFmpeg worker processes being killed by the OOM killer on Linux media pipelines
Parser warnings or errors originating from libavformat/iamf_parse.c in application logs

Detection Strategies

Inventory all deployed FFmpeg binaries and libraries; compare versions and commit hashes against the vulnerable range ending at 6e26f57f672b05e7b8b052007a83aef99dc81ccb.
Instrument media processing services with per-process memory ceilings and alert when FFmpeg workers cross defined thresholds during single-file processing.
Perform static analysis or SBOM queries to identify third-party applications that bundle vulnerable FFmpeg versions.

Monitoring Recommendations

Enable resource usage metrics (RSS, virtual memory) for FFmpeg-based services and forward them to a centralized telemetry backend.
Log the file types, sources, and sizes of media processed by transcoding workers to correlate memory anomalies with input characteristics.
Review FFmpeg stderr output for repeated parser errors referencing iamf or audio_element_obu.

How to Mitigate CVE-2025-1816

Immediate Actions Required

Update FFmpeg to a build that includes commit 0526535cd58444dd264e810b2f3348b4d96cff3b, which patches the leak in audio_element_obu.
Rebuild and redeploy any downstream applications that statically link libavformat from vulnerable FFmpeg sources.
Restrict IAMF file processing to trusted inputs until patched binaries are in production.

Patch Information

The FFmpeg maintainers fixed the issue in commit 0526535cd58444dd264e810b2f3348b4d96cff3b. Refer to the FFmpeg Commit Details for the exact code change, and pull the latest FFmpeg source from the FFmpeg Official Website. Package maintainers should rebuild distribution packages against the patched tree.

Workarounds

Disable or block IAMF parsing in FFmpeg-based services if IAMF support is not required for your workload.
Enforce strict memory and CPU limits on FFmpeg worker processes using cgroups, systemd unit resource controls, or container runtime constraints so leaks do not exhaust host memory.
Filter or sandbox untrusted media uploads to prevent adversary-controlled files from reaching the vulnerable parser.

bash

# Configuration example: constrain FFmpeg workers with systemd resource limits
# /etc/systemd/system/ffmpeg-worker.service.d/limits.conf
[Service]
MemoryMax=512M
MemoryHigh=384M
TasksMax=64
Restart=on-failure