{"id":"CVE-2026-125263","kind":"vulnerability","aliases":["CVE-2026-125263"],"related":[],"title":"FFmpeg: crafted LCEVC streams force huge allocations and exhaust memory","description":"FFmpeg 9.0 through 9.0.2 built with liblcevc_dec fails to validate LCEVC enhanced output dimensions against max_pixels in libavcodec/decode.c before frame allocation. Attackers can supply crafted H.264, HEVC or VVC streams declaring huge LCEVC resolutions to force oversized get_buffer2() allocations and exhaust memory.","summary":"FFmpeg 9.0 through 9.0.2 built with liblcevc_dec does not check LCEVC enhanced output dimensions against max_pixels before allocating frames. A crafted H.264, HEVC or VVC stream declaring a huge LCEVC resolution can force oversized buffer allocations and exhaust memory.","severity":"medium","cvss":5.7,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["ffmpeg","media-processing","runtime","video-transcoding"],"not_affected_if":["default-config","trusted-input-only"],"how_to_check":"- Run `ffmpeg -version` and check whether the version is `9.0` through `9.0.2`.\n- Check whether the build includes liblcevc_dec, for example with `ffmpeg -decoders | grep -i lcevc`.","fix":"- Move to a version later than `9.0.2` that is named in the patch linked from the NVD entry; the exact fixed version is unknown from the sources.","status":"open","published_at":"2026-11-09T20:18:12+00:00","first_seen_at":"2026-11-09T20:48:13+00:00","triaged_at":"2026-11-09T20:49:56+00:00","updated_at":"2026-11-09T20:49:56+00:00","category":"runtime","confidence":0.6,"triage":{"at":"2026-11-09T20:49:56Z","model":"claude-haiku-5-5","output":{"fix":"- Move to a version later than `9.0.2` that is named in the patch linked from the NVD entry; the exact fixed version is unknown from the sources.","reach":"network","title":"FFmpeg: crafted LCEVC streams force huge allocations and exhaust memory","impact":"medium","summary":"FFmpeg 9.0 through 9.0.2 built with liblcevc_dec does not check LCEVC enhanced output dimensions against max_pixels before allocating frames. A crafted H.264, HEVC or VVC stream declaring a huge LCEVC resolution can force oversized buffer allocations and exhaust memory.","audience":"businesses","category":"runtime","nicknames":[],"who_cares":["ffmpeg","media-processing","video-transcoding"],"confidence":0.6,"fix_status":"available","needs_auth":"no","worst_case":"Attacker exhausts server memory, crashing the decoding process","analyst_note":"Confirm the fixed version from the linked GitHub patch, since the sources do not state it.","how_to_check":"- Run `ffmpeg -version` and check whether the version is `9.0` through `9.0.2`.\n- Check whether the build includes liblcevc_dec, for example with `ffmpeg -decoders | grep -i lcevc`.","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":["default-config","trusted-input-only"],"who_is_affected":"Only builds of FFmpeg 9.0 through 9.0.2 compiled with liblcevc_dec are affected. Systems that decode untrusted media files or streams with such a build are the ones to look at; systems that only process trusted media or use other FFmpeg builds can skip it.","user_interaction":"no","product_ecosystem":"","needs_special_setup":"yes","severity_if_unknown":"medium"},"cost_usd":0.000773,"input_tokens":4633,"output_tokens":620,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-125263':13A,16A '-2026':12A,15A '9.0':26B,67C '9.0.2':28B,69C 'alloc':7A,44B,62B,88C,107C 'attack':89C 'buffer':61B 'buffer2':106C 'built':29B,70C 'check':35B 'craft':2A,47B,92C 'cve':11A,14A 'dec':32B,73C 'declar':53B,98C 'dimens':39B,80C 'enhanc':37B,78C 'exhaust':9A,64B,109C 'fail':74C 'ffmpeg':1A,17B,25B,66C 'forc':5A,59B,103C 'frame':45B,87C 'get':105C 'h.264':48B,93C 'hevc':49B,94C 'huge':6A,55B,99C 'lcevc':3A,36B,56B,77C,100C 'libavcodec/decode.c':85C 'liblcevc':31B,72C 'max':41B,82C 'media':19B 'media-process':18B 'memori':10A,65B,110C 'output':38B,79C 'overs':60B,104C 'pixel':42B,83C 'process':20B 'resolut':57B,101C 'runtim':21B 'stream':4A,52B,97C 'suppli':91C 'transcod':24B 'valid':76C 'video':23B 'video-transcod':22B 'vvc':51B,96C","nicknames":[],"mitigations":[],"who_affected":"Only builds of FFmpeg 9.0 through 9.0.2 compiled with liblcevc_dec are affected. Systems that decode untrusted media files or streams with such a build are the ones to look at; systems that only process trusted media or use other FFmpeg builds can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["ffmpeg","mediaprocessing","medium","runtime","videotranscoding"],"campaign_type":null,"search_a":"'-125263':13A,16A '-2026':12A,15A 'alloc':7A 'craft':2A 'cve':11A,14A 'exhaust':9A 'ffmpeg':1A 'forc':5A 'huge':6A 'lcevc':3A 'memori':10A 'stream':4A","search_b":"'9.0':26B '9.0.2':28B 'alloc':44B,62B 'buffer':61B 'built':29B 'check':35B 'craft':47B 'dec':32B 'declar':53B 'dimens':39B 'enhanc':37B 'exhaust':64B 'ffmpeg':17B,25B 'forc':59B 'frame':45B 'h.264':48B 'hevc':49B 'huge':55B 'lcevc':36B,56B 'liblcevc':31B 'max':41B 'media':19B 'media-process':18B 'memori':65B 'output':38B 'overs':60B 'pixel':42B 'process':20B 'resolut':57B 'runtim':21B 'stream':52B 'transcod':24B 'video':23B 'video-transcod':22B 'vvc':51B","search_c":"'9.0':67C '9.0.2':69C 'alloc':88C,107C 'attack':89C 'buffer2':106C 'built':70C 'craft':92C 'dec':73C 'declar':98C 'dimens':80C 'enhanc':78C 'exhaust':109C 'fail':74C 'ffmpeg':66C 'forc':103C 'frame':87C 'get':105C 'h.264':93C 'hevc':94C 'huge':99C 'lcevc':77C,100C 'libavcodec/decode.c':85C 'liblcevc':72C 'max':82C 'memori':110C 'output':79C 'overs':104C 'pixel':83C 'resolut':101C 'stream':97C 'suppli':91C 'valid':76C 'vvc':96C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-09T20:18:12+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:L/AC:H/AT:P/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-2026-125263","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-125263","severity":null,"published_at":"2026-11-09T20:18:12+00:00","modified_at":"2026-11-09T20:18:12+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":109737,"url":"https://github.com/FFmpeg/FFmpeg/commit/60b286521b46caa09792af04c6a4e3437aac8293","title":"Patch: github.com","kind":"other","source":"nvd","publisher":"vendor","text":null,"published_at":null,"relation":"fix","confidence":null,"note":"Patch: github.com"},{"id":109738,"url":"https://www.vulncheck.com/advisories/ffmpeg-9.0-through-9.0.2-memory-exhaustion-via-lcevc-enhancement-dimensions","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"}