CVE-2019-20386

Memory leak via unreleased event sources

Published Jan 21, 2020 · Updated Jun 9, 2025

Memory leak in systemd before 243 allows physically proximate attackers to consume systemd-logind memory through power-switch udev events. button_open replaces b->io_event_source with a new event source without first releasing the existing reference, so repeated change events leak memory. Reachability requires physical hardware events or root execution of udevadm trigger, and Red Hat reports that crashing logind is difficult.

CVSS severity2.4
Low
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leak in systemd before 243 allows physically proximate attackers to consume systemd-logind memory through power-switch udev events. button_open replaces b->io_event_source with a new event source without first releasing the existing reference, so repeated change events leak memory. Reachability requires physical hardware events or root execution of udevadm trigger, and Red Hat reports that crashing logind is difficult.

The record

CVE
CVE-2019-20386
Published
Jan 21, 2020
Updated
Jun 9, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-401
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 21, 2020CVE publishedPublication date reported by the CVE source.
  2. Jun 9, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

2.4UbuntuCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
5.1CISA-ADPCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
2.1NIST NVDAV:L/AC:L/Au:N/C:N/I:N/A:P
2.4NIST NVDCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
2.4Red HatCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-401Missing Release of Memory after Effective Lifetime

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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