High severity · published Jul 27, 2026
CVE-2026-42792
epmd permanent DoS via EMFILE on accept(2) in erts
7.5
CVSS
0.4%
EPSS
No
On KEV
Description
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. The 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. On 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. This issue affects OTP from OTP 17.0 before OTP 29.0.4, OTP 28.5.0.4 and OTP 27.3.4.15.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 38% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OT
OTP · Erlang
6.0; 17.0; 07b8f441ca711f9812fad9e9115bab3c3aa92f79 before 865d203e4a6a8f44179eced9e1428f9259e4a3bb · source: vendor
ER
Erlang/otp · Erlang
17.0 before 27.3.4; 28.0 before 28.5.0.4; 29.0 before 29.0.4 · source: NVD
ER
Erts · Erlang
6.0 before 15.2.7.11; 16.0 before 16.4.0.4; 17.0 before 17.0.4 · source: NVD
Affected product
OT
OTP
Erlang
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