{"id":"CVE-2026-125269","kind":"vulnerability","aliases":["CVE-2026-125269"],"related":[],"title":"FFmpeg: crafted H.264 stream triggers double free, corrupting heap memory","description":"FFmpeg through 9.0.2 contains a double free vulnerability in libavcodec/cbs_sei.c where cbs_sei_delete_message() leaves a stale extension_data reference that ff_cbs_sei_add_message() reuses. Attackers can supply a crafted H.264 stream with a display orientation SEI message followed by payload extension data, processed by h264_metadata with display_orientation=insert, to corrupt heap memory.","summary":"FFmpeg through 9.0.2 has a double free in its SEI handling code, reachable when h264_metadata processes a crafted H.264 stream with display orientation SEI and extension data. An attacker who gets such a file processed can corrupt heap memory, which can lead to code execution.","severity":"high","cvss":7.3,"epss":null,"exploited":false,"exploited_at":null,"products":[{"name":"FFmpeg","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["ffmpeg","h264","media-processing","runtime"],"not_affected_if":["filter-not-used","trusted-input-only"],"how_to_check":"- Check the installed FFmpeg version with `ffmpeg -version` and compare it to the fixed release in the product data (sources list FFmpeg through 9.0.2 as affected)\n- Look for workflows that run `h264_metadata` with `display_orientation=insert` on untrusted input","fix":"- FFmpeg: unknown (sources name the patch on github.com but do not state the fixed version)","status":"open","published_at":"2026-11-09T20:18:13+00:00","first_seen_at":"2026-11-09T20:48:14+00:00","triaged_at":"2026-11-09T20:49:44+00:00","updated_at":"2026-11-09T20:49:44+00:00","category":"runtime","confidence":0.6,"triage":{"at":"2026-11-09T20:49:44Z","model":"claude-haiku-5-5","output":{"fix":"- FFmpeg: unknown (sources name the patch on github.com but do not state the fixed version)","reach":"unknown","title":"FFmpeg: crafted H.264 stream triggers double free, corrupting heap memory","impact":"high","summary":"FFmpeg through 9.0.2 has a double free in its SEI handling code, reachable when h264_metadata processes a crafted H.264 stream with display orientation SEI and extension data. An attacker who gets such a file processed can corrupt heap memory, which can lead to code execution.","audience":"businesses","category":"runtime","nicknames":[],"who_cares":["ffmpeg","media-processing","h264"],"confidence":0.6,"fix_status":"available","needs_auth":"no","worst_case":"heap corruption in FFmpeg may lead to code execution","analyst_note":"Confirm the fixed FFmpeg version from the github.com patch and the vulncheck advisory; sources give no fixed version.","how_to_check":"- Check the installed FFmpeg version with `ffmpeg -version` and compare it to the fixed release in the product data (sources list FFmpeg through 9.0.2 as affected)\n- Look for workflows that run `h264_metadata` with `display_orientation=insert` on untrusted input","plain_action":"","product_name":"FFmpeg","needs_analyst":true,"not_affected_if":["trusted-input-only","filter-not-used"],"who_is_affected":"Systems that run FFmpeg on H.264 files from outside sources, such as media transcoding services or upload pipelines, are exposed when they use the h264_metadata filter with display_orientation=insert. Local use on trusted files, or builds that never run that filter, are unlikely to be affected.","user_interaction":"no","product_ecosystem":"vendor","needs_special_setup":"yes","severity_if_unknown":"high"},"cost_usd":0.000786,"input_tokens":4650,"output_tokens":642,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-125269':13A,16A '-2026':12A,15A '9.0.2':26B,72C 'add':95C 'attack':53B,98C 'cbs':81C,93C 'code':35B,68B 'contain':73C 'corrupt':8A,61B,125C 'craft':2A,42B,102C 'cve':11A,14A 'data':51B,89C,115C 'delet':83C 'display':46B,107C,121C 'doubl':6A,29B,75C 'execut':69B 'extens':50B,88C,114C 'ff':92C 'ffmpeg':1A,17A,18B,24B,70C 'file':58B 'follow':111C 'free':7A,30B,76C 'get':55B 'h.264':3A,43B,103C 'h264':19B,38B,118C 'handl':34B 'heap':9A,62B,126C 'insert':123C 'lead':66B 'leav':85C 'libavcodec/cbs_sei.c':79C 'media':21B 'media-process':20B 'memori':10A,63B,127C 'messag':84C,96C,110C 'metadata':39B,119C 'orient':47B,108C,122C 'payload':113C 'process':22B,40B,59B,116C 'reachabl':36B 'refer':90C 'reus':97C 'runtim':23B 'sei':33B,48B,82C,94C,109C 'stale':87C 'stream':4A,44B,104C 'suppli':100C 'trigger':5A 'vulner':77C","nicknames":[],"mitigations":[],"who_affected":"Systems that run FFmpeg on H.264 files from outside sources, such as media transcoding services or upload pipelines, are exposed when they use the h264_metadata filter with display_orientation=insert. Local use on trusted files, or builds that never run that filter, are unlikely to be affected.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":["ffmpeg"],"ptokens":["ffmpeg"],"labels":["ffmpeg","h264","high","mediaprocessing","runtime","vendor"],"campaign_type":null,"search_a":"'-125269':13A,16A '-2026':12A,15A 'corrupt':8A 'craft':2A 'cve':11A,14A 'doubl':6A 'ffmpeg':1A,17A 'free':7A 'h.264':3A 'heap':9A 'memori':10A 'stream':4A 'trigger':5A","search_b":"'9.0.2':26B 'attack':53B 'code':35B,68B 'corrupt':61B 'craft':42B 'data':51B 'display':46B 'doubl':29B 'execut':69B 'extens':50B 'ffmpeg':18B,24B 'file':58B 'free':30B 'get':55B 'h.264':43B 'h264':19B,38B 'handl':34B 'heap':62B 'lead':66B 'media':21B 'media-process':20B 'memori':63B 'metadata':39B 'orient':47B 'process':22B,40B,59B 'reachabl':36B 'runtim':23B 'sei':33B,48B 'stream':44B","search_c":"'9.0.2':72C 'add':95C 'attack':98C 'cbs':81C,93C 'contain':73C 'corrupt':125C 'craft':102C 'data':89C,115C 'delet':83C 'display':107C,121C 'doubl':75C 'extens':88C,114C 'ff':92C 'ffmpeg':70C 'follow':111C 'free':76C 'h.264':103C 'h264':118C 'heap':126C 'insert':123C 'leav':85C 'libavcodec/cbs_sei.c':79C 'memori':127C 'messag':84C,96C,110C 'metadata':119C 'orient':108C,122C 'payload':113C 'process':116C 'refer':90C 'reus':97C 'sei':82C,94C,109C 'stale':87C 'stream':104C 'suppli':100C 'vulner':77C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-09T20:18:13+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","cvss_by":"disclosure@vulncheck.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-125269","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-125269","severity":null,"published_at":"2026-11-09T20:18:13+00:00","modified_at":"2026-11-09T20:18:13+00:00","first_seen_at":"2026-11-09T20:48:14+00:00","fetched_at":"2026-11-09T20:48:14+00:00","note":null}],"documents":[{"id":109753,"url":"https://github.com/FFmpeg/FFmpeg/commit/2c515eea07df719379e7f73deeeb7ccb8768433f","title":"Patch: github.com","kind":"other","source":"nvd","publisher":"vendor","text":null,"published_at":null,"relation":"fix","confidence":null,"note":"Patch: github.com"},{"id":109754,"url":"https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-double-free-via-cbs-sei-delete-message-in-cbs-sei-c","title":"Third-party advisory: www.vulncheck.com","kind":"advisory","source":"nvd","publisher":"research","text":null,"published_at":null,"relation":"advisory","confidence":null,"note":"Third-party advisory: www.vulncheck.com"}],"disclosures":[],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}