Detections
Analytics

Echo: unbound: security update to 1.25.2

low Tenable Cloud Security Plugin ID 462098

Description

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

 - In NLnet Labs Unbound 1.16.2 up to and including 1.25.1, a similar vulnerability as with CVE-2026-40622 in
 the 'ghost domain names' family of attacks was found in Unbound that could extend the ghost domain window
 by up to one cached TTL configured value for A/AAAA glue records. Similar to other 'ghost domain names'
 attacks, an adversary needs to control a (ghost) zone and be able to query a vulnerable Unbound. A single
 client A/AAAA query can cause Unbound to overwrite the cached expired parent-side glue rrset and
 essentially extend the ghost domain window by up to one cached TTL configured value ('cache-max-ttl'). In
 configurations where 'harden-referral-path: yes' is used (non-default configuration), no client query is
 required since Unbound implicitly performs that query. This is a variant of CVE-2026-40622 which only
 addressed the NS query. (CVE-2026-42955)

Solution

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

See Also

https://advisory.echohq.com/cve/CVE-2026-42955

Plugin Details

Severity: Low

ID: 462098

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:P/A:N

CVSS Score Source: CVE-2026-42955

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:L/A:N

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-2026-42955