Echo: unbound: security update to 1.25.2

high Tenable Cloud Security Plugin ID 458866

Description

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

- In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, when downstream DNS-over-QUIC (DoQ) is enabled,
the first two bidirectional streams on a new QUIC connection (stream_id 0 and 4) bypass the per-stream
'quic-size' gate entirely, and large input buffers are allocated later, after only the 2-byte length
prefix has been received from the initial streams. As a result, a remote client can make Unbound exceed
the configured 'quic-size' limit with low-cost input. Using only one connection and two streams, each
sending a declared 65535-byte length prefix and then holding the streams open, a client can already
trivially make Unbound roughly allocate double that amount. This is a remote availability issue / memory-
accounting bypass in the downstream DoQ implementation that leads to denial of service for new DoQ
clients. This vulnerability needs Unbound to be compiled with DoQ support ('--with-libngtcp2') and the
'quic-port' to be configured for the listening interfaces. (CVE-2026-32665)

Solution

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

Plugin Details

Severity: High

ID: 458866

Version: Revision 1.1

Type: Local

Family: Echo Local Security Checks

Published: 10/2/2026

Updated: 10/2/2026

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.72

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

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

CVSS Score Source: CVE-2026-32665

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

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

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-2026-32665

Detections

Analytics