{"id":"CVE-2026-125095","kind":"vulnerability","aliases":["CVE-2026-125095"],"related":[],"title":"FFmpeg: crafted C93 video file leaks uninitialized stack memory into frames","description":"FFmpeg through 9.0.2 contains an uninitialized memory use vulnerability in the C93 video decoder in libavcodec/c93.c, where decode_frame() never checks how many color table bytes were copied. Attackers can supply a crafted truncated Interplay C93 file so draw_n_color() writes uninitialized stack bytes into decoded frames, disclosing stack memory contents.","summary":"FFmpeg's C93 video decoder in libavcodec never checks how many color table bytes were copied, so a crafted truncated Interplay C93 file makes it write uninitialized stack bytes into decoded frames. An attacker can read stack memory contents through the decoded output.","severity":"medium","cvss":4.8,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["ffmpeg","libavcodec","media-processing","package"],"not_affected_if":["c93-decoder-unused","no-untrusted-media"],"how_to_check":"- Check the installed FFmpeg version with `ffmpeg -version`; the sources cover releases through `9.0.2`.\n- Find whether the service decodes untrusted media with FFmpeg, since the flaw needs a crafted Interplay C93 file to be decoded.","fix":null,"status":"open","published_at":"2026-11-09T19:16:50+00:00","first_seen_at":"2026-11-09T19:28:15+00:00","triaged_at":"2026-11-09T19:33:40+00:00","updated_at":"2026-11-09T19:33:40+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-11-09T19:33:40Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"unknown","title":"FFmpeg: crafted C93 video file leaks uninitialized stack memory into frames","impact":"low","summary":"FFmpeg's C93 video decoder in libavcodec never checks how many color table bytes were copied, so a crafted truncated Interplay C93 file makes it write uninitialized stack bytes into decoded frames. An attacker can read stack memory contents through the decoded output.","audience":"businesses","category":"package","nicknames":[],"who_cares":["ffmpeg","libavcodec","media-processing"],"confidence":0.6,"fix_status":"unknown","needs_auth":"no","worst_case":"stack memory contents disclosed through decoded video frames","analyst_note":"Confirm the fixed FFmpeg version from the linked GitHub patch and check whether the C93 decoder is built into default distributions.","how_to_check":"- Check the installed FFmpeg version with `ffmpeg -version`; the sources cover releases through `9.0.2`.\n- Find whether the service decodes untrusted media with FFmpeg, since the flaw needs a crafted Interplay C93 file to be decoded.","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":["no-untrusted-media","c93-decoder-unused"],"who_is_affected":"Systems that decode untrusted or user-supplied video files with FFmpeg's libavcodec are exposed, since the flaw triggers on a crafted Interplay C93 file. Services that only process trusted media or do not run FFmpeg on uploaded content can skip it. The sources do not state a fixed version, though a patch is linked.","user_interaction":"yes","product_ecosystem":"","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000765,"input_tokens":4623,"output_tokens":605,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-125095':14A,17A '-2026':13A,16A '9.0.2':69C 'attack':57B,95C 'byte':37B,52B,92C,111C 'c93':3A,26B,45B,78C,102C 'check':32B,87C 'color':35B,90C,107C 'contain':70C 'content':62B,118C 'copi':39B,94C 'craft':2A,42B,99C 'cve':12A,15A 'decod':28B,54B,65B,80C,84C,113C 'disclos':115C 'draw':105C 'ffmpeg':1A,18B,24B,67C 'file':5A,46B,103C 'frame':11A,55B,85C,114C 'interplay':44B,101C 'leak':6A 'libavcodec':19B,30B 'libavcodec/c93.c':82C 'make':47B 'mani':34B,89C 'media':21B 'media-process':20B 'memori':9A,61B,73C,117C 'n':106C 'never':31B,86C 'output':66B 'packag':23B 'process':22B 'read':59B 'stack':8A,51B,60B,110C,116C 'suppli':97C 'tabl':36B,91C 'truncat':43B,100C 'uniniti':7A,50B,72C,109C 'use':74C 'video':4A,27B,79C 'vulner':75C 'write':49B,108C","nicknames":[],"mitigations":[],"who_affected":"Systems that decode untrusted or user-supplied video files with FFmpeg's libavcodec are exposed, since the flaw triggers on a crafted Interplay C93 file. Services that only process trusted media or do not run FFmpeg on uploaded content can skip it. The sources do not state a fixed version, though a patch is linked.","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":"'-125095':14A,17A '-2026':13A,16A 'c93':3A 'craft':2A 'cve':12A,15A 'ffmpeg':1A 'file':5A 'frame':11A 'leak':6A 'memori':9A 'stack':8A 'uniniti':7A 'video':4A","search_b":"'attack':57B 'byte':37B,52B 'c93':26B,45B 'check':32B 'color':35B 'content':62B 'copi':39B 'craft':42B 'decod':28B,54B,65B 'ffmpeg':18B,24B 'file':46B 'frame':55B 'interplay':44B 'libavcodec':19B,30B 'make':47B 'mani':34B 'media':21B 'media-process':20B 'memori':61B 'never':31B 'output':66B 'packag':23B 'process':22B 'read':59B 'stack':51B,60B 'tabl':36B 'truncat':43B 'uniniti':50B 'video':27B 'write':49B","search_c":"'9.0.2':69C 'attack':95C 'byte':92C,111C 'c93':78C,102C 'check':87C 'color':90C,107C 'contain':70C 'content':118C 'copi':94C 'craft':99C 'decod':80C,84C,113C 'disclos':115C 'draw':105C 'ffmpeg':67C 'file':103C 'frame':85C,114C 'interplay':101C 'libavcodec/c93.c':82C 'mani':89C 'memori':73C,117C 'n':106C 'never':86C 'stack':110C,116C 'suppli':97C 'tabl':91C 'truncat':100C 'uniniti':72C,109C 'use':74C 'video':79C 'vulner':75C 'write':108C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-09T19:16:50+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-2026-125095","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-125095","severity":null,"published_at":"2026-11-09T19:16:50+00:00","modified_at":"2026-11-09T19:16:50+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":109207,"url":"https://github.com/FFmpeg/FFmpeg/commit/ac0106851a4dac555c967421dfc96c0135183133","title":"Patch: github.com","kind":"other","source":"nvd","publisher":"vendor","text":null,"published_at":null,"relation":"fix","confidence":null,"note":"Patch: github.com"},{"id":109208,"url":"https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-c93-decoder-uninitialized-stack-memory-disclosure","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"}