CVE-2019-25031Network attack vector

Configuration modification via unsanitized downloaded list entries

Published Apr 27, 2021 · Updated Aug 5, 2024

Configuration injection in Unbound before 1.9.5 allows man-in-the-middle attackers to alter generated configuration via HTTP data. The contributed create_unbound_ad_servers.sh script downloads an ad-server list over cleartext HTTP and writes each unsanitized line into unbound_ad_servers, allowing extra directives on one line. Exploitation requires running this non-installed community script while an attacker can intercept its HTTP session; NLnet Labs disputes that the issue affects installed Unbound software.

CVSS severity5.9
Medium
EPSS probability1.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Configuration injection in Unbound before 1.9.5 allows man-in-the-middle attackers to alter generated configuration via HTTP data. The contributed create_unbound_ad_servers.sh script downloads an ad-server list over cleartext HTTP and writes each unsanitized line into unbound_ad_servers, allowing extra directives on one line. Exploitation requires running this non-installed community script while an attacker can intercept its HTTP session; NLnet Labs disputes that the issue affects installed Unbound software.

The record

CVE
CVE-2019-25031
Published
Apr 27, 2021
Updated
Aug 5, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-89, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 27, 2021CVE 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.9NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
5.3SUSECVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-89Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')
T1557Adversary-in-the-Middle

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo