{"id":"CVE-2026-125266","kind":"vulnerability","aliases":["CVE-2026-125266"],"related":[],"title":"FFmpeg: crafted SANM animation leaks decoder stack memory into video","description":"FFmpeg through 9.0.2 contains an uninitialized stack memory disclosure vulnerability in old_codec23() of libavcodec/sanm.c that leaks stack bytes into decoded frames. Attackers can supply a crafted LucasArts SMUSH/SANM animation using codec 23 with an inline table to expose decoder process stack memory in output video.","summary":"FFmpeg through 9.0.2 has an uninitialized stack memory read in the old_codec23() decoder in libavcodec/sanm.c. A crafted LucasArts SMUSH/SANM file using codec 23 can leak stack bytes into decoded output video.","severity":"medium","cvss":4.8,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["ffmpeg","libavcodec","media-processing","package"],"not_affected_if":["no-untrusted-media","sanm-not-decoded"],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-11-09T20:18:13+00:00","first_seen_at":"2026-11-09T20:48:14+00:00","triaged_at":"2026-11-09T20:50:00+00:00","updated_at":"2026-11-09T20:50:00+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-11-09T20:50:00Z","model":"claude-haiku-5-5","output":{"fix":"- unknown","reach":"unknown","title":"FFmpeg: crafted SANM animation leaks decoder stack memory into video","impact":"low","summary":"FFmpeg through 9.0.2 has an uninitialized stack memory read in the old_codec23() decoder in libavcodec/sanm.c. A crafted LucasArts SMUSH/SANM file using codec 23 can leak stack bytes into decoded output video.","audience":"businesses","category":"package","nicknames":[],"who_cares":["ffmpeg","libavcodec","media-processing"],"confidence":0.6,"fix_status":"unknown","needs_auth":"no","worst_case":"decoder stack bytes leak into output video frames","analyst_note":"Find the patch commit or fixed version range from the github.com patch link and confirm the affected version boundary; check the vulncheck advisory for exposure details.","how_to_check":"- unknown","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":["no-untrusted-media","sanm-not-decoded"],"who_is_affected":"Systems that decode untrusted SANM/SMUSH animation files with FFmpeg, such as media-processing services that accept user uploads. Installations that never decode these files are unlikely to be exposed. The sources do not state a fixed version beyond a patch link.","user_interaction":"unknown","product_ecosystem":"","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000709,"input_tokens":4617,"output_tokens":495,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-125266':13A,16A '-2026':12A,15A '23':46B,87C '9.0.2':25B,57C 'anim':4A,84C 'attack':77C 'byte':50B,73C 'codec':45B,86C 'codec23':35B,67C 'contain':58C 'craft':2A,40B,81C 'cve':11A,14A 'decod':6A,36B,52B,75C,94C 'disclosur':63C 'expos':93C 'ffmpeg':1A,17B,23B,55C 'file':43B 'frame':76C 'inlin':90C 'leak':5A,48B,71C 'libavcodec':18B 'libavcodec/sanm.c':38B,69C 'lucasart':41B,82C 'media':20B 'media-process':19B 'memori':8A,30B,62C,97C 'old':34B,66C 'output':53B,99C 'packag':22B 'process':21B,95C 'read':31B 'sanm':3A 'smush/sanm':42B,83C 'stack':7A,29B,49B,61C,72C,96C 'suppli':79C 'tabl':91C 'uniniti':28B,60C 'use':44B,85C 'video':10A,54B,100C 'vulner':64C","nicknames":[],"mitigations":[],"who_affected":"Systems that decode untrusted SANM/SMUSH animation files with FFmpeg, such as media-processing services that accept user uploads. Installations that never decode these files are unlikely to be exposed. The sources do not state a fixed version beyond a patch link.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["ffmpeg","libavcodec","mediaprocessing","medium","package"],"campaign_type":null,"search_a":"'-125266':13A,16A '-2026':12A,15A 'anim':4A 'craft':2A 'cve':11A,14A 'decod':6A 'ffmpeg':1A 'leak':5A 'memori':8A 'sanm':3A 'stack':7A 'video':10A","search_b":"'23':46B '9.0.2':25B 'byte':50B 'codec':45B 'codec23':35B 'craft':40B 'decod':36B,52B 'ffmpeg':17B,23B 'file':43B 'leak':48B 'libavcodec':18B 'libavcodec/sanm.c':38B 'lucasart':41B 'media':20B 'media-process':19B 'memori':30B 'old':34B 'output':53B 'packag':22B 'process':21B 'read':31B 'smush/sanm':42B 'stack':29B,49B 'uniniti':28B 'use':44B 'video':54B","search_c":"'23':87C '9.0.2':57C 'anim':84C 'attack':77C 'byte':73C 'codec':86C 'codec23':67C 'contain':58C 'craft':81C 'decod':75C,94C 'disclosur':63C 'expos':93C 'ffmpeg':55C 'frame':76C 'inlin':90C 'leak':71C 'libavcodec/sanm.c':69C 'lucasart':82C 'memori':62C,97C 'old':66C 'output':99C 'process':95C 'smush/sanm':83C 'stack':61C,72C,96C 'suppli':79C 'tabl':91C 'uniniti':60C 'use':85C 'video':100C 'vulner':64C","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:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:N/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-2026-125266","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-125266","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":109746,"url":"https://github.com/FFmpeg/FFmpeg/commit/d42cb1925987cc27899441ce39fa7bd2647dc72e","title":"Patch: github.com","kind":"other","source":"nvd","publisher":"vendor","text":null,"published_at":null,"relation":"fix","confidence":null,"note":"Patch: github.com"},{"id":109747,"url":"https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-uninitialized-stack-memory-disclosure-via-sanm-codec-23","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"}