{"id":"CVE-2026-104895","kind":"vulnerability","aliases":["CVE-2026-104895"],"related":[],"title":"Jackson Smile parser: crafted input forces huge allocation, crashes async endpoints","description":"The asynchronous Smile parser (NonBlockingByteArrayParser) uses a raw-binary length prefix taken from untrusted input to allocate a byte[] before the body is read, with no upper bound and no overflow check. On the raw-binary marker 0xFD, _decodeVInt() computes (value << 6) + (i & 0x3F) without the (value >>> 25) != 0 overflow guard present in the blocking SmileParser._readUnsignedVInt, and _startRawBinary then allocates the declared length immediately.\n\n\n\nA Smile feed of roughly ten bytes can therefore force an eager allocation of approximately 2 GB, producing an OutOfMemoryError on reactive or asynchronous Smile endpoints. A VInt crafted to overflow int yields a negative length and a NegativeArraySizeException, a RuntimeException that is not a JacksonException and so escapes the parser contract. Either outcome crashes the request or processing thread.\n\n\n\nThis is the same class of issue as CVE-2020-28491 in the CBOR parser of this library, which was fixed with a LONGEST_NON_CHUNKED_BINARY guard; the asynchronous Smile parser never received the equivalent guard. No privileges or user interaction beyond the ability to submit data for parsing are required.","summary":"The asynchronous Smile parser (NonBlockingByteArrayParser) trusts a length prefix from input and allocates that many bytes before reading the body, with no upper bound or overflow check. A roughly ten-byte Smile feed can trigger about 2 GB of allocation (OutOfMemoryError) or a negative length (NegativeArraySizeException), crashing the request or processing thread.","severity":"high","cvss":7.5,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["jackson","java","package","reactive","smile-format","spring-webflux"],"not_affected_if":["blocking-parser-only","no-smile-input"],"how_to_check":"- Check whether the project depends on the Jackson Smile dataformat, for example with `mvn dependency:tree` or `gradle dependencies` and look for jackson-dataformat-smile.\n- Check whether any reactive or asynchronous endpoint parses Smile input through the non-blocking parser.\n- Check the installed jackson-dataformat-smile version against the affected range in the advisory (unknown from the sources).","fix":"- Upgrade jackson-dataformat-smile to the patched release listed in the advisory (unknown from the sources).\n- Until patched, reject or stop accepting Smile input on asynchronous endpoints.","status":"open","published_at":"2026-10-28T00:17:11+00:00","first_seen_at":"2026-10-28T00:29:54+00:00","triaged_at":"2026-10-28T00:31:37+00:00","updated_at":"2026-10-28T00:31:37+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-10-28T00:31:37Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade jackson-dataformat-smile to the patched release listed in the advisory (unknown from the sources).\n- Until patched, reject or stop accepting Smile input on asynchronous endpoints.","reach":"unknown","title":"Jackson Smile parser: crafted input forces huge allocation, crashes async endpoints","impact":"medium","summary":"The asynchronous Smile parser (NonBlockingByteArrayParser) trusts a length prefix from input and allocates that many bytes before reading the body, with no upper bound or overflow check. A roughly ten-byte Smile feed can trigger about 2 GB of allocation (OutOfMemoryError) or a negative length (NegativeArraySizeException), crashing the request or processing thread.","category":"package","nicknames":[],"who_cares":["java","jackson","reactive","spring-webflux","smile-format"],"confidence":0.7,"needs_auth":"no","worst_case":"Crafted Smile input crashes the request or processing thread via memory exhaustion.","analyst_note":"Find the patched jackson-dataformat-smile version and affected range in the NVD entry or the upstream Jackson advisory for CVE-2026-104895.","how_to_check":"- Check whether the project depends on the Jackson Smile dataformat, for example with `mvn dependency:tree` or `gradle dependencies` and look for jackson-dataformat-smile.\n- Check whether any reactive or asynchronous endpoint parses Smile input through the non-blocking parser.\n- Check the installed jackson-dataformat-smile version against the affected range in the advisory (unknown from the sources).","needs_analyst":true,"not_affected_if":["no-smile-input","blocking-parser-only"],"who_is_affected":"Applications that use the Jackson Smile dataformat and parse Smile data through the asynchronous, non-blocking parser, especially reactive endpoints that accept data from clients. Services that do not accept Smile input, or that use only the blocking SmileParser, are not described as affected by the sources.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"high"},"cost_usd":0.001155,"input_tokens":3651,"output_tokens":1579,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-104895':14A,17A '-2020':216C '-2026':13A,16A '-28491':217C '0':131C '0x3f':126C '0xfd':120C '2':65B,162C '25':130C '6':124C 'abil':251C 'alloc':8A,40B,68B,98C,142C,159C 'approxim':161C 'async':10A 'asynchron':29B,82C,170C,236C 'beyond':249C 'binari':90C,118C,233C 'block':137C 'bodi':47B,103C 'bound':51B,109C 'byte':43B,59B,100C,153C 'cbor':220C 'check':54B,113C 'chunk':232C 'class':211C 'comput':122C 'contract':198C 'craft':4A,175C 'crash':9A,75B,201C 'cve':12A,15A,215C 'data':254C 'declar':144C 'decodevint':121C 'eager':158C 'either':199C 'endpoint':11A,172C 'equival':242C 'escap':195C 'feed':61B,149C 'fix':227C 'forc':6A,156C 'format':24B 'gb':66B,163C 'guard':133C,234C,243C 'huge':7A 'immedi':146C 'input':5A,38B,96C 'int':178C 'interact':248C 'issu':213C 'jackson':1A,18B 'jacksonexcept':192C 'java':19B 'length':35B,73B,91C,145C,182C 'librari':224C 'longest':230C 'mani':42B 'marker':119C 'negat':72B,181C 'negativearraysizeexcept':74B,185C 'never':239C 'non':231C 'nonblockingbytearraypars':32B,85C 'outcom':200C 'outofmemoryerror':69B,166C 'overflow':53B,112C,132C,177C 'packag':20B 'pars':256C 'parser':3A,31B,84C,197C,221C,238C 'prefix':36B,92C 'present':134C 'privileg':245C 'process':79B,205C 'produc':164C 'raw':89C,117C 'raw-binari':88C,116C 'reactiv':21B,168C 'read':45B,105C 'receiv':240C 'request':77B,203C 'requir':258C 'rough':56B,151C 'runtimeexcept':187C 'smile':2A,23B,30B,60B,83C,148C,171C,237C 'smile-format':22B 'smileparser._readunsignedvint':138C 'spring':26B 'spring-webflux':25B 'startrawbinari':140C 'submit':253C 'taken':93C 'ten':58B,152C 'ten-byt':57B 'therefor':155C 'thread':80B,206C 'trigger':63B 'trust':33B 'untrust':95C 'upper':50B,108C 'use':86C 'user':247C 'valu':123C,129C 'vint':174C 'webflux':27B 'without':127C 'yield':179C","nicknames":[],"mitigations":[],"who_affected":"Applications that use the Jackson Smile dataformat and parse Smile data through the asynchronous, non-blocking parser, especially reactive endpoints that accept data from clients. Services that do not accept Smile input, or that use only the blocking SmileParser, are not described as affected by the sources.","tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-28T00:17:11+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cvss_by":"36c7be3b-2937-45df-85ea-ca7133ea542c","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-104895","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-104895","severity":null,"published_at":"2026-10-28T00:17:11+00:00","modified_at":"2026-10-28T00:17:11+00:00","first_seen_at":"2026-10-28T00:29:54+00:00","fetched_at":"2026-10-28T00:29:54+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"}