Detections
Analytics

Echo: unbound: security update to 1.25.2

medium Tenable Cloud Security Plugin ID 460043

Description

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

 - In NLnet Labs Unbound 1.7.0 up to and including 1.25.1, when the 'dnscrypt:' clause lists more 'dnscrypt-
 provider-cert:' files than there are matching 'dnscrypt-secret-key:' files, Unbound fills only the matched
 prefix and leaves the tail slots at the '0xdb' fill that libsodium's allocator writes into every
 allocation. Unbound would then iterate over the number of cert files, not the actual slots, so it walks
 into a slot with garbage data filled with '0xdb' bytes. Any unauthenticated client that sends one UDP
 datagram of ≥ 68 bytes whose first 8 bytes are '0xdb' to 'dnscrypt-port' will use that garbage entry which
 leads to a garbage dereference killing the server. This is a silent faulty configuration that goes
 unnoticed until triggered with the right client query. Unbound needs to be compiled with DNSCrypt support
 ('--enable-dnscrypt'). (CVE-2026-55990)

Solution

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

See Also

https://advisory.echohq.com/cve/CVE-2026-55990

Plugin Details

Severity: Medium

ID: 460043

Version: Revision 1.1

Type: Local

Published: 10/2/2026

Updated: 10/2/2026

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.63

CVSS v2

Risk Factor: Medium

Base Score: 5.4

Temporal Score: 4

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

CVSS Score Source: CVE-2026-55990

CVSS v3

Risk Factor: Medium

Base Score: 5.9

Temporal Score: 5.2

Vector: CVSS:3.0/AV:N/AC:H/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-2026-55990