CVE-2019-19344Network attack vector

Service interruption via DNS scavenging use-after-free

Published Jan 21, 2020 · Updated Aug 5, 2024

Use-after-free in Samba AD DC allows remote authenticated users to interrupt service through DNS zone scavenging of expired records. The dns_tombstone_records_zone path reallocates a buffer while local variables retain pointers to the original freed storage, which is then read and can place stale memory into the DNS database during NDR validation. Exposure requires the off-by-default dns zone scavenging setting on an affected AD DC, bounding the risk to configured domain controllers rather than ordinary Samba file servers.

CVSS severity6.5
Medium
EPSS probability2.76%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Samba AD DC allows remote authenticated users to interrupt service through DNS zone scavenging of expired records. The dns_tombstone_records_zone path reallocates a buffer while local variables retain pointers to the original freed storage, which is then read and can place stale memory into the DNS database during NDR validation. Exposure requires the off-by-default dns zone scavenging setting on an affected AD DC, bounding the risk to configured domain controllers rather than ordinary Samba file servers.

The record

CVE
CVE-2019-19344
Published
Jan 21, 2020
Updated
Aug 5, 2024
Vendor
Red Hat
Product
Samba
Classifications
CWE-416, T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 21, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=all samba 4.10.x versions before 4.10.12
  2. Affected versionversion=all samba 4.11.x versions before 4.11.5
  3. Affected versionversion=all samba 4.9.x versions before 4.9.18

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Red Hat · Sambaversion=all samba 4.10.x versions before 4.10.12; version=all samba 4.11.x versions before 4.11.5; version=all samba 4.9.x versions before 4.9.18

Published CVSS scores

6.5Samba TeamCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1499Endpoint Denial of Service

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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