{"id":"CVE-2026-125066","kind":"vulnerability","aliases":["CVE-2026-125066"],"related":[],"title":"FFmpeg: crafted AVI file crashes decoder via NULL pointer dereference","description":"FFmpeg through 9.0.2 contains a NULL pointer dereference vulnerability in the Cirrus Logic AccuPak (CLJR) decoder in libavcodec/cljrdec.c because decode_frame() ignores init_get_bits() failure. Attackers can supply a crafted AVI file with a 2^28-byte CLJR frame that overflows the bit count, causing reads from a NULL buffer and crashing the process.","summary":"FFmpeg's Cirrus Logic AccuPak (CLJR) decoder ignores a bit-reader initialization failure, so a crafted AVI file with an oversized frame causes a NULL buffer read. An attacker gets the FFmpeg process to crash when it opens the file.","severity":"medium","cvss":6.8,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["ffmpeg","libavcodec","media-processing","package"],"not_affected_if":["no-untrusted-media-input"],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-11-09T19:16:48+00:00","first_seen_at":"2026-11-09T19:28:15+00:00","triaged_at":"2026-11-09T19:31:47+00:00","updated_at":"2026-11-09T19:31:47+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-11-09T19:31:47Z","model":"claude-haiku-5-5","output":{"fix":"- unknown","reach":"unknown","title":"FFmpeg: crafted AVI file crashes decoder via NULL pointer dereference","impact":"low","summary":"FFmpeg's Cirrus Logic AccuPak (CLJR) decoder ignores a bit-reader initialization failure, so a crafted AVI file with an oversized frame causes a NULL buffer read. An attacker gets the FFmpeg process to crash when it opens the file.","audience":"developers","category":"package","nicknames":[],"who_cares":["ffmpeg","libavcodec","media-processing"],"confidence":0.6,"fix_status":"unknown","needs_auth":"no","worst_case":"Denial of service: the decoding process crashes on a crafted file","analyst_note":"Find the fixed FFmpeg version and the patch commit from the linked fix and the NVD entry; confirm the reach of the flaw.","how_to_check":"- unknown","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":["no-untrusted-media-input"],"who_is_affected":"Applications that use FFmpeg's libavcodec to decode untrusted AVI files with the CLJR codec are exposed to a crash. The sources do not say which FFmpeg versions carry the fix or which configurations are affected beyond the decoder itself.","user_interaction":"unknown","product_ecosystem":"","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000712,"input_tokens":4654,"output_tokens":494,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-125066':13A,16A '-2026':12A,15A '2':99C '28':100C '9.0.2':66C 'accupak':27B,77C 'attack':52B,90C 'avi':3A,40B,95C 'bit':33B,88C,107C 'bit-read':32B 'buffer':49B,114C 'byte':101C 'caus':46B,109C 'cirrus':25B,75C 'cljr':28B,78C,102C 'contain':67C 'count':108C 'craft':2A,39B,94C 'crash':5A,58B,116C 'cve':11A,14A 'decod':6A,29B,79C,83C 'derefer':10A,71C 'failur':36B,89C 'ffmpeg':1A,17B,23B,55B,64C 'file':4A,41B,63B,96C 'frame':45B,84C,103C 'get':53B,87C 'ignor':30B,85C 'init':86C 'initi':35B 'libavcodec':18B 'libavcodec/cljrdec.c':81C 'logic':26B,76C 'media':20B 'media-process':19B 'null':8A,48B,69C,113C 'open':61B 'overflow':105C 'overs':44B 'packag':22B 'pointer':9A,70C 'process':21B,56B,118C 'read':50B,110C 'reader':34B 'suppli':92C 'via':7A 'vulner':72C","nicknames":[],"mitigations":[],"who_affected":"Applications that use FFmpeg's libavcodec to decode untrusted AVI files with the CLJR codec are exposed to a crash. The sources do not say which FFmpeg versions carry the fix or which configurations are affected beyond the decoder itself.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"developers","plain_action":null,"pkeys":[],"ptokens":[],"labels":["ffmpeg","libavcodec","mediaprocessing","medium","package"],"campaign_type":null,"search_a":"'-125066':13A,16A '-2026':12A,15A 'avi':3A 'craft':2A 'crash':5A 'cve':11A,14A 'decod':6A 'derefer':10A 'ffmpeg':1A 'file':4A 'null':8A 'pointer':9A 'via':7A","search_b":"'accupak':27B 'attack':52B 'avi':40B 'bit':33B 'bit-read':32B 'buffer':49B 'caus':46B 'cirrus':25B 'cljr':28B 'craft':39B 'crash':58B 'decod':29B 'failur':36B 'ffmpeg':17B,23B,55B 'file':41B,63B 'frame':45B 'get':53B 'ignor':30B 'initi':35B 'libavcodec':18B 'logic':26B 'media':20B 'media-process':19B 'null':48B 'open':61B 'overs':44B 'packag':22B 'process':21B,56B 'read':50B 'reader':34B","search_c":"'2':99C '28':100C '9.0.2':66C 'accupak':77C 'attack':90C 'avi':95C 'bit':88C,107C 'buffer':114C 'byte':101C 'caus':109C 'cirrus':75C 'cljr':78C,102C 'contain':67C 'count':108C 'craft':94C 'crash':116C 'decod':79C,83C 'derefer':71C 'failur':89C 'ffmpeg':64C 'file':96C 'frame':84C,103C 'get':87C 'ignor':85C 'init':86C 'libavcodec/cljrdec.c':81C 'logic':76C 'null':69C,113C 'overflow':105C 'pointer':70C 'process':118C 'read':110C 'suppli':92C 'vulner':72C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-09T19:16:48+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/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-2026-125066","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-125066","severity":null,"published_at":"2026-11-09T19:16:48+00:00","modified_at":"2026-11-09T19:16:48+00:00","first_seen_at":"2026-11-09T19:28:15+00:00","fetched_at":"2026-11-09T19:28:15+00:00","note":null}],"documents":[{"id":109191,"url":"https://github.com/FFmpeg/FFmpeg/commit/d40c1b12811814fc6c2d0816527b003d8510ea06","title":"Patch: github.com","kind":"other","source":"nvd","publisher":"vendor","text":null,"published_at":null,"relation":"fix","confidence":null,"note":"Patch: github.com"},{"id":109192,"url":"https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-null-pointer-dereference-in-cljr-video-decoder","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"}