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Echo: unbound: security update to 1.25.2

low Tenable Self-Hosted Container Security Plugin ID 461956

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

 - In NLnet Labs Unbound 1.13.2 up to and including 1.25.1, stub or forward zones where the name is below an
 intermediate labed below a DNSSEC signed zone could be shadowed by the intermediate label's secure
 NXDOMAIN answer from the parent. This is caused by an off-by-one error in 'harden-below-nxdomain' logic;
 enabled by default. It effectively bypasses the configuration and the configured stub/forward zone is
 never contacted. 'harden-below-nxdomain' does an upward DNS cache walk together with a delegation point
 guard that does not allow NXDOMAIN synthesis above stub/forward zones. The guard tests the domain name but
 before stripping a label. This results in an iteration where the domain name equals the configured
 stub/forward zone apex that passes the guard, strips one more label, and probes the cache at the apex's
 immediate public parent. If that parent has a cached DNSSEC-secure NXDOMAIN, which it will for any private
 namespace nested two or more labels under a signed public name, the walk returns it and the configured
 stub/forward upstream is never contacted. This can only be triggered by the query for the intermediate
 label (between the stub/forward apex and the DNSSEC parent zone). (CVE-2026-44687)

Solution

Update the unbound library and its related packages to version 1.25.2 or later.

See Also

https://advisory.echohq.com/cve/CVE-2026-44687

Plugin Details

Severity: Low

ID: 461956

Version: Revision 1.1

Type: Local

Published: 10/2/2026

Updated: 10/2/2026

Risk Information

VPR

Risk Factor: Low

Score: 1.2

Percentile: 0.01

CVSS v2

Risk Factor: Low

Base Score: 2.6

Temporal Score: 1.9

Vector: CVSS2#AV:N/AC:H/Au:N/C:N/I:N/A:P

CVSS Score Source: CVE-2026-44687

CVSS v3

Risk Factor: Low

Base Score: 3.7

Temporal Score: 3.2

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

Exploit Ease: No known exploits are available

Patch Publication Date: 7/23/2026

Vulnerability Publication Date: 7/22/2026

Reference Information

CVE: CVE-2026-44687