{"id":"CVE-2026-125253","kind":"vulnerability","aliases":["CVE-2026-125253"],"related":[],"title":"FFmpeg: crafted VP9 packet overflows size check, crashing 32-bit builds","description":"FFmpeg through 9.0.2 contains an integer overflow in cbs_vp9_split_fragment() in libavcodec/cbs_vp9.c that wraps the superframe size check on 32-bit builds. Attackers can supply a crafted VP9 packet with a forged superframe index containing near-2^32 frame sizes, causing out-of-bounds reads that crash 32-bit applications.","summary":"FFmpeg's VP9 superframe parser miscalculates frame sizes on 32-bit builds due to an integer overflow in cbs_vp9_split_fragment(). A crafted VP9 packet with a forged superframe index causes out-of-bounds reads that crash the application.","severity":"medium","cvss":5.8,"epss":null,"exploited":false,"exploited_at":null,"products":[{"name":"FFmpeg","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["32-bit","ffmpeg","libavcodec","runtime","vp9"],"not_affected_if":["64-bit-build","trusted-input-only"],"how_to_check":"- Check the FFmpeg version with `ffmpeg -version`, and compare it against the fixed version.\n- Confirm whether you run a 32-bit FFmpeg build (unknown whether the sources give a command for this).","fix":null,"status":"open","published_at":"2026-11-09T20:18:11+00:00","first_seen_at":"2026-11-09T20:48:13+00:00","triaged_at":"2026-11-09T20:49:54+00:00","updated_at":"2026-11-09T20:49:54+00:00","category":"runtime","confidence":0.6,"triage":{"at":"2026-11-09T20:49:54Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"unknown","title":"FFmpeg: crafted VP9 packet overflows size check, crashing 32-bit builds","impact":"low","summary":"FFmpeg's VP9 superframe parser miscalculates frame sizes on 32-bit builds due to an integer overflow in cbs_vp9_split_fragment(). A crafted VP9 packet with a forged superframe index causes out-of-bounds reads that crash the application.","audience":"businesses","category":"runtime","nicknames":[],"who_cares":["ffmpeg","libavcodec","vp9","32-bit"],"confidence":0.6,"fix_status":"unknown","needs_auth":"no","worst_case":"32-bit applications crash after parsing a crafted VP9 packet","analyst_note":"Confirm the fixed FFmpeg version and whether the patch at the linked GitHub commit covers all branches; the sources give no version range.","how_to_check":"- Check the FFmpeg version with `ffmpeg -version`, and compare it against the fixed version.\n- Confirm whether you run a 32-bit FFmpeg build (unknown whether the sources give a command for this).","plain_action":"","product_name":"FFmpeg","needs_analyst":true,"not_affected_if":["64-bit-build","trusted-input-only"],"who_is_affected":"Applications that decode untrusted VP9 media on 32-bit FFmpeg builds are the exposed case, since the overflow only wraps the size check there. The sources describe a crash (out-of-bounds read), not code execution. Systems that only process trusted media or run 64-bit builds can likely skip it, but the sources do not state this explicitly.","user_interaction":"unknown","product_ecosystem":"vendor","needs_special_setup":"yes","severity_if_unknown":"unknown"},"cost_usd":0.000779,"input_tokens":4642,"output_tokens":629,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-125253':14A,17A '-2':104C '-2026':13A,16A '32':9A,19B,34B,87C,105C,116C '9.0.2':68C 'applic':65B,118C 'attack':90C 'bit':10A,20B,35B,88C,117C 'bound':60B,112C 'build':11A,36B,89C 'caus':56B,108C 'cbs':43B,74C 'check':7A,85C 'contain':69C,102C 'craft':2A,48B,94C 'crash':8A,63B,115C 'cve':12A,15A 'due':37B 'ffmpeg':1A,18A,21B,25B,66C 'forg':53B,99C 'fragment':46B,77C 'frame':31B,106C 'index':55B,101C 'integ':40B,71C 'libavcodec':22B 'libavcodec/cbs_vp9.c':79C 'miscalcul':30B 'near':103C 'out-of-bound':57B,109C 'overflow':5A,41B,72C 'packet':4A,50B,96C 'parser':29B 'read':61B,113C 'runtim':23B 'size':6A,32B,84C,107C 'split':45B,76C 'superfram':28B,54B,83C,100C 'suppli':92C 'vp9':3A,24B,27B,44B,49B,75C,95C 'wrap':81C","nicknames":[],"mitigations":[],"who_affected":"Applications that decode untrusted VP9 media on 32-bit FFmpeg builds are the exposed case, since the overflow only wraps the size check there. The sources describe a crash (out-of-bounds read), not code execution. Systems that only process trusted media or run 64-bit builds can likely skip it, but the sources do not state this explicitly.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":["ffmpeg"],"ptokens":["ffmpeg"],"labels":["32bit","ffmpeg","libavcodec","medium","runtime","vendor","vp9"],"campaign_type":null,"search_a":"'-125253':14A,17A '-2026':13A,16A '32':9A 'bit':10A 'build':11A 'check':7A 'craft':2A 'crash':8A 'cve':12A,15A 'ffmpeg':1A,18A 'overflow':5A 'packet':4A 'size':6A 'vp9':3A","search_b":"'32':19B,34B 'applic':65B 'bit':20B,35B 'bound':60B 'build':36B 'caus':56B 'cbs':43B 'craft':48B 'crash':63B 'due':37B 'ffmpeg':21B,25B 'forg':53B 'fragment':46B 'frame':31B 'index':55B 'integ':40B 'libavcodec':22B 'miscalcul':30B 'out-of-bound':57B 'overflow':41B 'packet':50B 'parser':29B 'read':61B 'runtim':23B 'size':32B 'split':45B 'superfram':28B,54B 'vp9':24B,27B,44B,49B","search_c":"'-2':104C '32':87C,105C,116C '9.0.2':68C 'applic':118C 'attack':90C 'bit':88C,117C 'bound':112C 'build':89C 'caus':108C 'cbs':74C 'check':85C 'contain':69C,102C 'craft':94C 'crash':115C 'ffmpeg':66C 'forg':99C 'fragment':77C 'frame':106C 'index':101C 'integ':71C 'libavcodec/cbs_vp9.c':79C 'near':103C 'out-of-bound':109C 'overflow':72C 'packet':96C 'read':113C 'size':84C,107C 'split':76C 'superfram':83C,100C 'suppli':92C 'vp9':75C,95C 'wrap':81C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-09T20:18:11+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:P/VC:L/VI:N/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-2026-125253","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-125253","severity":null,"published_at":"2026-11-09T20:18:11+00:00","modified_at":"2026-11-09T20:18:11+00:00","first_seen_at":"2026-11-09T20:48:13+00:00","fetched_at":"2026-11-09T20:48:13+00:00","note":null}],"documents":[{"id":109717,"url":"https://github.com/FFmpeg/FFmpeg/commit/6280907da48c4dd78f95ef5c713a29c7702153a3","title":"Patch: github.com","kind":"other","source":"nvd","publisher":"vendor","text":null,"published_at":null,"relation":"fix","confidence":null,"note":"Patch: github.com"},{"id":109718,"url":"https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-vp9-cbs-superframe-integer-overflow-out-of-bounds-read","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"}