CVE-2026-42792
epmd permanent DoS via EMFILE on accept(2) in erts
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.
INFO
Published Date :
July 27, 2026, 4:17 p.m.
Last Modified :
July 27, 2026, 6:16 p.m.
Remotely Exploit :
Yes !
Source :
6b3ad84c-e1a6-4bf7-a703-f496b71e49db
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 4.0 | MEDIUM | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | ||||
| CVSS 4.0 | MEDIUM | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db |
Solution
- Update Erlang OTP to a version that resolves the described issue.
- Configure file descriptor limits appropriately.
- Apply systemd configuration changes if applicable.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-42792.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-42792 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-42792
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-42792 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-42792 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 27, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-42792', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-27T17:25:58.879765Z'} -
New CVE Received by 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Jul. 27, 2026
Action Type Old Value New Value Added Affected [{'cpes': ['cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*'], 'repo': 'https://github.com/erlang/otp', 'vendor': 'Erlang', 'modules': ['epmd_srv'], 'product': 'OTP', 'versions': [{'status': 'affected', 'changes': [{'at': '17.0.4', 'status': 'unaffected'}, {'at': '16.4.0.4', 'status': 'unaffected'}, {'at': '15.2.7.11', 'status': 'unaffected'}], 'version': '6.0', 'lessThan': '*', 'versionType': 'otp'}], 'packageURL': 'pkg:otp/erts?repository_url=https:%2F%2Fgithub.com%2Ferlang%2Fotp&vcs_url=git%20https:%2F%2Fgithub.com%2Ferlang%2Fotp.git', 'packageName': 'erts', 'programFiles': ['epmd/src/epmd_srv.c'], 'defaultStatus': 'unaffected', 'programRoutines': [{'name': 'do_accept'}]}, {'cpes': ['cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*'], 'repo': 'https://github.com/erlang/otp', 'vendor': 'Erlang', 'modules': ['epmd_srv'], 'product': 'OTP', 'versions': [{'status': 'affected', 'changes': [{'at': '29.0.4', 'status': 'unaffected'}, {'at': '28.5.0.4', 'status': 'unaffected'}, {'at': '27.3.4.15', 'status': 'unaffected'}], 'version': '17.0', 'lessThan': '*', 'versionType': 'otp'}, {'status': 'affected', 'version': '07b8f441ca711f9812fad9e9115bab3c3aa92f79', 'lessThan': '865d203e4a6a8f44179eced9e1428f9259e4a3bb', 'versionType': 'git'}], 'packageURL': 'pkg:github/erlang/otp', 'packageName': 'erlang/otp', 'programFiles': ['erts/epmd/src/epmd_srv.c'], 'collectionURL': 'https://github.com', 'defaultStatus': 'unaffected', 'programRoutines': [{'name': 'do_accept'}]}] Added 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. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/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 Added CWE CWE-755 Added CWE CWE-770 Added Reference https://cna.erlef.org/cves/CVE-2026-42792.html Added Reference https://github.com/erlang/otp/commit/865d203e4a6a8f44179eced9e1428f9259e4a3bb Added Reference https://github.com/erlang/otp/security/advisories/GHSA-h6f3-hx58-xhj6 Added Reference https://osv.dev/vulnerability/EEF-CVE-2026-42792 Added Reference https://www.erlang.org/doc/system/versions.html#order-of-versions