{"id":"CVE-2026-42792","aliases":["EEF-CVE-2026-42792","GHSA-h6f3-hx58-xhj6"],"url":"https://o3.security/vulnerability/CVE-2026-42792","summary":"epmd permanent DoS via EMFILE on accept(2) in erts","details":"Improper Handling of Exceptional Conditions vulnerability in Erlang OTP erts (epmd) allows an unauthenticated remote attacker to permanently terminate the Erlang Port Mapper Daemon (epmd) via connection slot exhaustion.\n\nThe do_accept function in erts/epmd/src/epmd_srv.c calls epmd_cleanup_exit() when accept(2) returns EMFILE (per-process file descriptor limit reached) or ENFILE (system-wide file descriptor limit reached), rather than treating these as recoverable conditions. An attacker can exhaust epmd's file descriptor slots by holding many TCP connections open while periodically sending a single byte to reset the idle timeout, then causing accept(2) to return EMFILE, which kills the daemon. epmd has no per-source-IP connection cap, making the attack feasible from a single source.\n\nOn Debian/Ubuntu default packaging the impact is amplified: the systemd unit inherits a low file descriptor soft limit, and repeated daemon deaths trigger systemd's start-rate-limit, permanently failing both epmd.service and epmd.socket and requiring manual operator intervention to recover.\n\nThis issue affects OTP from OTP 17.0 before OTP 29.0.4, OTP 28.5.0.4 and OTP 27.3.4.15.","published":"2026-07-27T14:58:24.426Z","modified":"2026-08-07T21:27:23.527309Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[],"fix":{"url":"https://github.com/erlang/otp/commit/865d203e4a6a8f44179eced9e1428f9259e4a3bb","label":"erlang/otp@865d203"},"references":[{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-42792.html"},{"type":"WEB","url":"https://github.com"},{"type":"WEB","url":"https://osv.dev/vulnerability/EEF-CVE-2026-42792"},{"type":"WEB","url":"https://www.erlang.org/doc/system/versions.html#order-of-versions"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42792.json"},{"type":"ADVISORY","url":"https://github.com/erlang/otp/security/advisories/GHSA-h6f3-hx58-xhj6"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42792"},{"type":"FIX","url":"https://github.com/erlang/otp/commit/865d203e4a6a8f44179eced9e1428f9259e4a3bb"},{"type":"PACKAGE","url":"https://github.com/erlang/otp"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T21:27:23.527309Z"}}