CVE-2026-52295: 
Ffmpeg vulnerability analysis and mitigation

CVE-2026-52295 is a buffer overflow / out-of-bounds read vulnerability in FFmpeg affecting versions 7.0 and later (before 9.0), located in the libavformat/iamf_writer.c component. The flaw arises because copied extradata buffers lack the required padding before GetBitContext-based bitreader access in the fill_codec_config and update_extradata functions. It was discovered by Kenan Alghythee (University of Illinois Chicago) and collaborators, disclosed and published on September 1, 2026. The CVSS v3.1 base score is 2.9 (Low) per NVD, though the GitHub Advisory Database assigns a score of 6.2 (Moderate) with a different vector (GitHub Advisory, Researcher Reference).

The root cause is classified as CWE-125 (Out-of-bounds Read) and CWE-120 (Buffer Copy without Checking Size of Input). In libavformat/iamf_writer.c, extradata is copied or allocated without appending the padding bytes required by FFmpeg's GetBitContext bitreader, which reads slightly beyond the declared buffer boundary. This was introduced by commits 25835e25931c and 56d630e6c2ae3033a124133c42308b5edbd0fc98. An attacker can trigger the flaw by supplying a crafted IAMF-format media file to FFmpeg, causing a heap-buffer-overflow on read. The attack vector is local with high complexity and requires no privileges or user interaction (GitHub Advisory, Researcher Reference).

Successful exploitation results in a crash or denial-of-service condition in the FFmpeg process, as the heap out-of-bounds read causes abnormal termination. There is no impact on confidentiality or integrity — the vulnerability is limited to availability. Applications and services that rely on FFmpeg for automated media processing (e.g., transcoding pipelines, streaming servers) could be disrupted if fed crafted IAMF input (GitHub Advisory, Researcher Reference).

There is no public proof-of-concept exploit and no evidence of in-the-wild exploitation at this time. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. The EPSS score is approximately 0.17% (2nd percentile), indicating a low near-term exploitation probability. NVD's SSVC assessment classifies exploitation as "none" and the attack as non-automatable (GitHub Advisory).

1. Craft malicious IAMF input: Prepare a media file with a crafted IAMF codec configuration block where the extradata section is sized to trigger the missing-padding condition in fill_codec_config or update_extradata within libavformat/iamf_writer.c.
2. Deliver the file to FFmpeg: Pass the crafted file as input to a vulnerable FFmpeg instance (versions 7.0–8.x before the fix), e.g., via ffmpeg -i malicious.iamf output.mp4 or through an application that invokes FFmpeg programmatically.
3. Trigger out-of-bounds read: FFmpeg's GetBitContext bitreader accesses memory beyond the allocated extradata buffer due to missing padding, causing a heap-buffer-overflow on read.
4. Achieve denial of service: The process crashes (SIGABRT or SIGSEGV under ASan/normal operation), disrupting any service relying on FFmpeg for media processing (Researcher Reference, GitHub Advisory).

• Process: FFmpeg process terminating unexpectedly (SIGABRT, SIGSEGV, or heap-buffer-overflow error) when processing IAMF-format or MOV/IAMF-embedded media files.
• Logs: ASan or system crash logs referencing libavformat/iamf_writer.c functions fill_codec_config or update_extradata; stack traces involving GetBitContext.
• File System: Presence of crafted .iamf or .mov files with anomalous extradata section sizes in input directories monitored by FFmpeg-based services.
• Network: Unexpected upload of unusual IAMF media files to services that invoke FFmpeg for transcoding, particularly files with minimal or malformed codec configuration blocks (Researcher Reference).

Upgrade FFmpeg to version 9.0 or later, which includes the fix merged via PR #22988 (commit 8439e0203744a30d280668fcd086f74ed5001da1). As a workaround, restrict processing of untrusted IAMF-format media files, validate and sanitize all input provided to FFmpeg, and implement input size limits on IAMF format processing. Detection plugins are available in Qualys (ID: 6288004) and Nessus (ID: 342622) for identifying vulnerable FFmpeg installations (GitHub Advisory, Researcher Reference).

The vulnerability was reported by Kenan Alghythee and collaborators from the SySec Research Group at the University of Illinois Chicago, Texas A&M University–San Antonio, and Indiana University Bloomington. The upstream FFmpeg project merged the fixes in PR #22988 and subsequently requested CVE assignment from MITRE. No significant broader media coverage or notable community debate has been observed, consistent with the vulnerability's low severity and limited exploitation potential (Researcher Reference).