{"id":"CVE-2026-65631","kind":"vulnerability","aliases":["CVE-2026-65631"],"related":[],"title":"erlang-jose: crafted RSA JWK parsing exhausts CPU, denying service","description":"Inefficient Algorithmic Complexity in erlang-jose allows an unauthenticated remote attacker to cause a CPU-exhaustion denial of service by submitting a crafted RSA JSON Web Key.\n\nWhen an application parses an untrusted JWK through the public jose_jwk:from_binary/1 or jose_jwk:from_map/1 API (or the Elixir wrappers JOSE.JWK.from_binary/1 and JOSE.JWK.from_map/1), an RSA private key that supplies d, e, and n but omits all Chinese Remainder Theorem parameters (p, q, dp, dq, qi) is routed into convert_sfm_to_crt/1, which tries to recover the missing primes by factoring the modulus. The three integers are read straight from the base64url input and are never validated as a real RSA key. When the modulus cannot be split into two factors (for example, when it is itself prime), the search loop convert_sfm_to_crt_find_p/6 performs a modular exponentiation over the attacker-sized modulus on every iteration and never succeeds. A single request of a few hundred bytes forces close to one CPU-second of work before an internal one-second watchdog kills the worker, and a larger modulus raises the cost further. By flooding such requests an attacker can saturate every scheduler and deny service, without credentials, a valid RSA key, or any special configuration.\n\nThis issue affects jose: from 1.7.7 before 1.11.13.","summary":"The erlang-jose library, used by Elixir and Erlang apps, spends about a CPU-second per crafted RSA JSON Web Key when parsing it, because it tries to factor the modulus. An unauthenticated attacker flooding such requests can saturate every scheduler and deny service.","severity":"medium","cvss":6.9,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["api","elixir","erlang","jose","package","self-hosted"],"not_affected_if":["jose-below-1.7.7","no-untrusted-jwk-input"],"how_to_check":"- Check the locked jose version in `mix.lock` (Elixir) or `rebar.lock` (Erlang) and see if it is from `1.7.7` up to but not including `1.11.13`.\n- Look for code that calls `JOSE.JWK.from_binary/1`, `JOSE.JWK.from_map/1`, `jose_jwk:from_binary/1` or `jose_jwk:from_map/1` on untrusted input.","fix":"- Upgrade jose to `1.11.13` or later.\n- Until upgraded, avoid parsing attacker-supplied JWKs through these functions, or rate-limit the endpoints that accept them.","status":"open","published_at":"2026-10-26T20:17:58+00:00","first_seen_at":"2026-10-26T20:50:18+00:00","triaged_at":"2026-10-26T20:51:42+00:00","updated_at":"2026-10-26T20:51:42+00:00","category":"package","confidence":0.8,"triage":{"at":"2026-10-26T20:51:42Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade jose to `1.11.13` or later.\n- Until upgraded, avoid parsing attacker-supplied JWKs through these functions, or rate-limit the endpoints that accept them.","reach":"internet","title":"erlang-jose: crafted RSA JWK parsing exhausts CPU, denying service","impact":"medium","summary":"The erlang-jose library, used by Elixir and Erlang apps, spends about a CPU-second per crafted RSA JSON Web Key when parsing it, because it tries to factor the modulus. An unauthenticated attacker flooding such requests can saturate every scheduler and deny service.","category":"package","nicknames":[],"who_cares":["elixir","erlang","jose","self-hosted","api"],"confidence":0.8,"needs_auth":"no","worst_case":"Saturated schedulers cause denial of service for the whole application","analyst_note":"","how_to_check":"- Check the locked jose version in `mix.lock` (Elixir) or `rebar.lock` (Erlang) and see if it is from `1.7.7` up to but not including `1.11.13`.\n- Look for code that calls `JOSE.JWK.from_binary/1`, `JOSE.JWK.from_map/1`, `jose_jwk:from_binary/1` or `jose_jwk:from_map/1` on untrusted input.","needs_analyst":false,"not_affected_if":["no-untrusted-jwk-input","jose-below-1.7.7"],"who_is_affected":"Applications that parse untrusted JWKs with erlang-jose's public from_binary or from_map functions are exposed, because the flaw is reached by a single request carrying a crafted RSA key with no CRT parameters. Systems that only handle keys they load from trusted local configuration, or that do not accept JWKs from outside, can skip it.","user_interaction":"no","needs_special_setup":"no","severity_if_unknown":"medium"},"cost_usd":0.000702,"input_tokens":3702,"output_tokens":664,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-2026':13A,16A '-65631':14A,17A '1.11.13':295C '1.7.7':293C 'affect':290C 'algorithm':73C 'allow':79C 'api':18B,120C 'app':36B 'applic':103C 'attack':61B,83C,221C,270C 'attacker-s':220C 'base64url':178C 'binary/1':114C,126C 'byte':237C 'cannot':192C 'caus':85C 'chines':143C 'close':239C 'complex':74C 'configur':287C 'convert':155C,208C 'cost':263C 'cpu':9A,41B,88C,243C 'cpu-exhaust':87C 'cpu-second':40B,242C 'craft':4A,44B,96C 'credenti':279C 'crt':211C 'crt/1':158C 'cve':12A,15A 'd':136C 'deni':10A,70B,276C 'denial':90C 'dp':149C 'dq':150C 'e':137C 'elixir':19B,33B,123C 'erlang':2A,20B,28B,35B,77C 'erlang-jos':1A,27B,76C 'everi':67B,225C,273C 'exampl':199C 'exhaust':8A,89C 'exponenti':217C 'factor':56B,167C,197C 'find':212C 'flood':62B,266C 'forc':238C 'host':25B 'hundr':236C 'ineffici':72C 'input':179C 'integ':172C 'intern':249C 'issu':289C 'iter':226C 'jose':3A,21B,29B,78C,111C,116C,291C 'jose.jwk.from':125C,128C 'json':46B,98C 'jwk':6A,107C,112C,117C 'key':48B,100C,133C,188C,283C 'kill':254C 'larger':259C 'librari':30B 'loop':207C 'map/1':119C,129C 'miss':164C 'modular':216C 'modulus':58B,169C,191C,223C,260C 'n':139C 'never':182C,228C 'omit':141C 'one':241C,251C 'one-second':250C 'p':147C 'p/6':213C 'packag':22B 'paramet':146C 'pars':7A,50B,104C 'per':43B 'perform':214C 'prime':165C,204C 'privat':132C 'public':110C 'q':148C 'qi':151C 'rais':261C 'read':174C 'real':186C 'recov':162C 'remaind':144C 'remot':82C 'request':64B,232C,268C 'rout':153C 'rsa':5A,45B,97C,131C,187C,282C 'satur':66B,272C 'schedul':68B,274C 'search':206C 'second':42B,244C,252C 'self':24B 'self-host':23B 'servic':11A,71B,92C,277C 'sfm':156C,209C 'singl':231C 'size':222C 'special':286C 'spend':37B 'split':194C 'straight':175C 'submit':94C 'succeed':229C 'suppli':135C 'theorem':145C 'three':171C 'tri':54B,160C 'two':196C 'unauthent':60B,81C 'untrust':106C 'use':31B 'valid':183C,281C 'watchdog':253C 'web':47B,99C 'without':278C 'work':246C 'worker':256C 'wrapper':124C","nicknames":[],"mitigations":[],"who_affected":"Applications that parse untrusted JWKs with erlang-jose's public from_binary or from_map functions are exposed, because the flaw is reached by a single request carrying a crafted RSA key with no CRT parameters. Systems that only handle keys they load from trusted local configuration, or that do not accept JWKs from outside, can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-26T20:17:58+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/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":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-65631","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-65631","severity":null,"published_at":"2026-10-26T20:17:58+00:00","modified_at":"2026-10-26T20:17:58+00:00","first_seen_at":"2026-10-26T20:50:18+00:00","fetched_at":"2026-10-26T20:50:18+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"}