{"id":"CVE-2026-57192","kind":"vulnerability","aliases":["CVE-2026-57192"],"related":[],"title":"Asterisk: Codec2 decoder heap overflow lets authenticated SIP callers corrupt memory","description":"Asterisk is an open source private branch exchange and telephony toolkit. Prior to Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3, an authenticated attacker may cause a heap buffer overflow through an out-of-bounds write in the `Codec2` decoder caused by a `floor/ceil sample-count mismatch`. The `codec_codec2` module must be loaded and `Codec2` must be configured on the attacked endpoint. The attacker must pass SIP authentication by username/password or `source IP address matching`, establish a call using `Codec2`, and send carefully crafted `Codec2` audio packets. This issue is fixed in Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3.","summary":"Asterisk's Codec2 audio decoder writes past a heap buffer when a call sends crafted Codec2 packets, because the floor and ceil sample counts do not match. An authenticated SIP caller can use this to corrupt memory in the PBX process.","severity":"medium","cvss":6.0,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["asterisk","pbx","runtime","sip","voip"],"not_affected_if":["codec2-not-enabled","codec2-not-loaded","fixed-version"],"how_to_check":"- Run `asterisk -rx \"core show version\"` and compare against the fixed releases.\n- Check whether the `codec_codec2` module is loaded with `asterisk -rx \"module show like codec2\"`.\n- Check whether Codec2 is enabled in SIP peer or endpoint configuration, for example `grep -i codec2 /etc/asterisk/*.conf`.","fix":"- Upgrade Asterisk to `20.20.1`, `21.12.3`, `22.10.1` or `23.4.1`, or Certified Asterisk to `20.7-cert11` or `22.8-cert3`.\n- Until upgraded, unload `codec_codec2` or remove Codec2 from endpoint codec lists.","status":"open","published_at":"2026-10-27T22:17:27+00:00","first_seen_at":"2026-10-27T22:29:29+00:00","triaged_at":"2026-10-27T22:30:17+00:00","updated_at":"2026-10-27T22:30:17+00:00","category":"runtime","confidence":0.6,"triage":{"at":"2026-10-27T22:30:17Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade Asterisk to `20.20.1`, `21.12.3`, `22.10.1` or `23.4.1`, or Certified Asterisk to `20.7-cert11` or `22.8-cert3`.\n- Until upgraded, unload `codec_codec2` or remove Codec2 from endpoint codec lists.","reach":"network","title":"Asterisk: Codec2 decoder heap overflow lets authenticated SIP callers corrupt memory","impact":"medium","summary":"Asterisk's Codec2 audio decoder writes past a heap buffer when a call sends crafted Codec2 packets, because the floor and ceil sample counts do not match. An authenticated SIP caller can use this to corrupt memory in the PBX process.","category":"runtime","nicknames":[],"who_cares":["asterisk","voip","sip","pbx"],"confidence":0.6,"needs_auth":"yes","worst_case":"Authenticated caller corrupts PBX process memory, possibly executing code.","analyst_note":"","how_to_check":"- Run `asterisk -rx \"core show version\"` and compare against the fixed releases.\n- Check whether the `codec_codec2` module is loaded with `asterisk -rx \"module show like codec2\"`.\n- Check whether Codec2 is enabled in SIP peer or endpoint configuration, for example `grep -i codec2 /etc/asterisk/*.conf`.","needs_analyst":false,"not_affected_if":["codec2-not-loaded","codec2-not-enabled","fixed-version"],"who_is_affected":"Systems running Asterisk that load the codec_codec2 module and offer Codec2 to SIP endpoints. Attackers must first pass SIP authentication, by username and password or by a matching source IP address, so exposure depends on who can register or call in. Deployments that do not load codec_codec2 or do not enable Codec2 can skip it.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"medium"},"cost_usd":0.0007,"input_tokens":3515,"output_tokens":696,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-2026':13A,16A '-57192':14A,17A '20.20.1':78C,164C '20.7':85C,171C '21.12.3':79C,165C '22.10.1':80C,166C '22.8':87C,173C '23.4.1':81C,167C 'address':144C 'asterisk':1A,18B,23B,64C,77C,84C,163C,170C 'attack':91C,131C,134C 'audio':26B,156C 'authent':7A,51B,90C,138C 'bound':103C 'branch':70C 'buffer':32B,96C 'call':35B,148C 'caller':9A,53B 'care':153C 'caus':93C,109C 'ceil':44B 'cert11':86C,172C 'cert3':88C,174C 'certifi':83C,169C 'codec':118C 'codec2':2A,25B,38B,107C,119C,125C,150C,155C 'configur':128C 'corrupt':10A,58B 'count':46B,115C 'craft':37B,154C 'cve':12A,15A 'decod':3A,27B,108C 'endpoint':132C 'establish':146C 'exchang':71C 'fix':161C 'floor':42B 'floor/ceil':112C 'heap':4A,31B,95C 'ip':143C 'issu':159C 'let':6A 'load':123C 'match':49B,145C 'may':92C 'memori':11A,59B 'mismatch':116C 'modul':120C 'must':121C,126C,135C 'open':67C 'out-of-bound':100C 'overflow':5A,97C 'packet':39B,157C 'pass':136C 'past':29B 'pbx':19B,62B 'prior':75C 'privat':69C 'process':63B 'runtim':20B 'sampl':45B,114C 'sample-count':113C 'send':36B,152C 'sip':8A,21B,52B,137C 'sourc':68C,142C 'telephoni':73C 'toolkit':74C 'use':55B,149C 'username/password':140C 'voip':22B 'write':28B,104C","nicknames":[],"mitigations":[],"who_affected":"Systems running Asterisk that load the codec_codec2 module and offer Codec2 to SIP endpoints. Attackers must first pass SIP authentication, by username and password or by a matching source IP address, so exposure depends on who can register or call in. Deployments that do not load codec_codec2 or do not enable Codec2 can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-27T22:17:27+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/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":"security-advisories@github.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-57192","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-57192","severity":null,"published_at":"2026-10-27T22:17:27+00:00","modified_at":"2026-10-27T22:17:27+00:00","first_seen_at":"2026-10-27T22:29:29+00:00","fetched_at":"2026-10-27T22:29:29+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}