EEF-CVE-2026-42792

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Source
https://cna.erlef.org/osv/EEF-CVE-2026-42792.html
Import Source
https://cna.erlef.org/osv/EEF-CVE-2026-42792.json
JSON Data
https://api.osv.dev/v1/vulns/EEF-CVE-2026-42792
Aliases
  • CVE-2026-42792
  • GHSA-h6f3-hx58-xhj6
Published
2026-07-27T14:58:24.426Z
Modified
2026-07-27T20:01:03.581556Z
Severity
  • 6.3 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N CVSS Calculator
Summary
epmd permanent DoS via EMFILE on accept(2) in erts
Details

Summary

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.

Workaround

* Restrict epmd to loopback only by adding a systemd socket override: set ListenStream= (empty, to clear), then ListenStream=127.0.0.1:4369 and ListenStream=[::1]:4369 in /etc/systemd/system/epmd.socket.d/override.conf. * On systemd-managed systems, raise the file descriptor limit and configure automatic restart by adding LimitNOFILE=65536 and Restart=always with a suitable RestartSec in /etc/systemd/system/epmd.service.d/override.conf. * Restrict network access to TCP port 4369 via firewall rules to trusted hosts only.

Database specific 
{
    "cwe_ids": [
        "CWE-755",
        "CWE-770"
    ],
    "capec_ids": [
        "CAPEC-227"
    ],
    "cpe_ids": [
        "cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"
    ]
}
References
Credits
    • Ryan Moore - FINDER
    • John Högberg - REMEDIATION_DEVELOPER

Affected packages

Git / github.com/erlang/otp

Affected ranges

Type
GIT
Repo
https://github.com/erlang/otp
Events
Introduced
07b8f441ca711f9812fad9e9115bab3c3aa92f79
Fixed
865d203e4a6a8f44179eced9e1428f9259e4a3bb

Affected versions

OTP-17.*
OTP-17.0
OTP-18.*
OTP-18.0
OTP-18.0-rc1
OTP-19.*
OTP-19.0
OTP-19.0-rc1
OTP-19.0-rc2
OTP-20.*
OTP-20.0
OTP-20.0-rc1
OTP-20.0-rc2
OTP-21.*
OTP-21.0
OTP-21.0-rc1
OTP-21.0-rc2
OTP-22.*
OTP-22.0
OTP-22.0-rc1
OTP-22.0-rc2
OTP-22.0-rc3
OTP-23.*
OTP-23.0
OTP-23.0-rc1
OTP-23.0-rc2
OTP-23.0-rc3
OTP-24.*
OTP-24.0
OTP-24.0-rc1
OTP-24.0-rc2
OTP-24.0-rc3
OTP-25.*
OTP-25.0
OTP-25.0-rc1
OTP-25.0-rc2
OTP-25.0-rc3
OTP-26.*
OTP-26.0
OTP-26.0-rc1
OTP-26.0-rc2
OTP-26.0-rc3
OTP-27.*
OTP-27.0
OTP-27.0-rc1
OTP-27.0-rc2
OTP-27.0-rc3
OTP-27.1
OTP-27.2
OTP-27.3
OTP-27.3.1
OTP-27.3.2
OTP-27.3.3
OTP-27.3.4
Other
patch-base-27

Database specific

source 
"https://cna.erlef.org/osv/EEF-CVE-2026-42792.json"
vanir_signatures_modified 
"2026-07-27T20:01:03Z"
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