{"id":"CVE-2026-125243","kind":"vulnerability","aliases":["CVE-2026-125243"],"related":[],"title":"FFmpeg: crafted JPEG-LS image leaks leftover heap memory in decoded frames","description":"FFmpeg through 9.0.2 contains an uninitialized memory disclosure vulnerability in ff_jpegls_decode_picture() in libavcodec/jpeglsdec.c, which decodes 16-bit line-interleaved JPEG-LS scans as 8-bit samples. Attackers can supply a crafted single-component JPEG-LS image with the ILV byte set to 1, causing decoded GRAY16 frames to expose leftover heap memory.","summary":"FFmpeg's JPEG-LS decoder mishandles 16-bit line-interleaved scans by decoding them as 8-bit samples. A crafted single-component JPEG-LS image makes decoded GRAY16 frames expose uninitialized heap memory.","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-jpegls-input"],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-11-09T19:17:02+00:00","first_seen_at":"2026-11-09T19:28:20+00:00","triaged_at":"2026-11-09T19:32:13+00:00","updated_at":"2026-11-09T19:32:13+00:00","category":"package","confidence":0.5,"triage":{"at":"2026-11-09T19:32:13Z","model":"claude-haiku-5-5","output":{"fix":"- unknown","reach":"unknown","title":"FFmpeg: crafted JPEG-LS image leaks leftover heap memory in decoded frames","impact":"low","summary":"FFmpeg's JPEG-LS decoder mishandles 16-bit line-interleaved scans by decoding them as 8-bit samples. A crafted single-component JPEG-LS image makes decoded GRAY16 frames expose uninitialized heap memory.","audience":"businesses","category":"package","nicknames":[],"who_cares":["ffmpeg","libavcodec","media-processing"],"confidence":0.5,"fix_status":"unknown","needs_auth":"no","worst_case":"heap memory contents leak into decoded image output","analyst_note":"Confirm the fixed FFmpeg version and check the vulncheck advisory and the linked patch for affected version ranges.","how_to_check":"- unknown","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":["no-untrusted-jpegls-input"],"who_is_affected":"Systems that run FFmpeg and decode untrusted JPEG-LS images, such as media ingestion or transcoding services, could leak heap contents into output frames. Installations that never decode JPEG-LS from untrusted sources have much less exposure.","user_interaction":"no","product_ecosystem":"","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000706,"input_tokens":4656,"output_tokens":480,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-125243':16A,19A '-2026':15A,18A '1':112C '16':33B,81C '8':43B,91C '9.0.2':65C 'attack':94C 'bit':34B,44B,82C,92C 'byte':109C 'caus':113C 'compon':50B,101C 'contain':66C 'craft':2A,47B,98C 'cve':14A,17A 'decod':12A,31B,40B,56B,75C,80C,114C 'disclosur':70C 'expos':59B,118C 'ff':73C 'ffmpeg':1A,20B,26B,63C 'frame':13A,58B,116C 'gray16':57B,115C 'heap':9A,61B,120C 'ilv':108C 'imag':6A,54B,105C 'interleav':37B,85C 'jpeg':4A,29B,52B,87C,103C 'jpeg-l':3A,28B,51B,86C,102C 'jpegl':74C 'leak':7A 'leftov':8A,119C 'libavcodec':21B 'libavcodec/jpeglsdec.c':78C 'line':36B,84C 'line-interleav':35B,83C 'ls':5A,30B,53B,88C,104C 'make':55B 'media':23B 'media-process':22B 'memori':10A,62B,69C,121C 'mishandl':32B 'packag':25B 'pictur':76C 'process':24B 'sampl':45B,93C 'scan':38B,89C 'set':110C 'singl':49B,100C 'single-compon':48B,99C 'suppli':96C 'uniniti':60B,68C 'vulner':71C","nicknames":[],"mitigations":[],"who_affected":"Systems that run FFmpeg and decode untrusted JPEG-LS images, such as media ingestion or transcoding services, could leak heap contents into output frames. Installations that never decode JPEG-LS from untrusted sources have much less exposure.","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":"'-125243':16A,19A '-2026':15A,18A 'craft':2A 'cve':14A,17A 'decod':12A 'ffmpeg':1A 'frame':13A 'heap':9A 'imag':6A 'jpeg':4A 'jpeg-l':3A 'leak':7A 'leftov':8A 'ls':5A 'memori':10A","search_b":"'16':33B '8':43B 'bit':34B,44B 'compon':50B 'craft':47B 'decod':31B,40B,56B 'expos':59B 'ffmpeg':20B,26B 'frame':58B 'gray16':57B 'heap':61B 'imag':54B 'interleav':37B 'jpeg':29B,52B 'jpeg-l':28B,51B 'libavcodec':21B 'line':36B 'line-interleav':35B 'ls':30B,53B 'make':55B 'media':23B 'media-process':22B 'memori':62B 'mishandl':32B 'packag':25B 'process':24B 'sampl':45B 'scan':38B 'singl':49B 'single-compon':48B 'uniniti':60B","search_c":"'1':112C '16':81C '8':91C '9.0.2':65C 'attack':94C 'bit':82C,92C 'byte':109C 'caus':113C 'compon':101C 'contain':66C 'craft':98C 'decod':75C,80C,114C 'disclosur':70C 'expos':118C 'ff':73C 'ffmpeg':63C 'frame':116C 'gray16':115C 'heap':120C 'ilv':108C 'imag':105C 'interleav':85C 'jpeg':87C,103C 'jpeg-l':86C,102C 'jpegl':74C 'leftov':119C 'libavcodec/jpeglsdec.c':78C 'line':84C 'line-interleav':83C 'ls':88C,104C 'memori':69C,121C 'pictur':76C 'sampl':93C 'scan':89C 'set':110C 'singl':100C 'single-compon':99C 'suppli':96C 'uniniti':68C 'vulner':71C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-09T19:17:02+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-2026-125243","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-125243","severity":null,"published_at":"2026-11-09T19:17:02+00:00","modified_at":"2026-11-09T19:17:02+00:00","first_seen_at":"2026-11-09T19:28:20+00:00","fetched_at":"2026-11-09T19:28:20+00:00","note":null}],"documents":[{"id":109376,"url":"https://github.com/FFmpeg/FFmpeg/commit/60bc31fcf6543505e6d2fc1a9399cca95f54ba4d","title":"Patch: github.com","kind":"other","source":"nvd","publisher":"vendor","text":null,"published_at":null,"relation":"fix","confidence":null,"note":"Patch: github.com"},{"id":109377,"url":"https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-uninitialized-memory-disclosure-via-jpeg-ls-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"}