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Echo: unbound: security update to 1.25.1-1

medium Tenable Self-Hosted Container Security Plugin ID 462696

Description

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

 - NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability when handling replies with very
 large RRsets that Unbound needs to perform name compression for. Malicious upstream responses with very
 large RRsets with records that don't share a suffix above the root can cause Unbound to spend a
 considerable time applying name compression to downstream replies. This can lead to degraded performance
 and eventually denial of service in well orchestrated attacks. An adversary can exploit the vulnerability
 by querying Unbound for the specially crafted contents of a malicious zone with very large RRsets. Before
 Unbound replies to the query it will try to apply name compression which was an unbounded operation that
 could lock the CPU until the whole packet was complete. A compression limit was introduced in 1.21.1 for
 this but it didn't account for the case where records would not share any suffix above the root. That
 causes Unbound to go in a different code path because of the compression tree lookup failure and
 eventually not increment the compression counter for those operations. Unbound 1.25.1 contains a patch
 with a fix that increments the compression counter regardless of the compression tree lookup. This is a
 complement fix to CVE-2024-8508. (CVE-2026-44390)

Solution

Update the unbound library and its related packages to version 1.25.1-1 or later.

See Also

https://advisory.echohq.com/cve/CVE-2026-44390

Plugin Details

Severity: Medium

ID: 462696

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: Medium

Base Score: 5

Temporal Score: 3.7

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

CVSS Score Source: CVE-2026-44390

CVSS v3

Risk Factor: Medium

Base Score: 5.3

Temporal Score: 4.6

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

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

CVSS v4

Risk Factor: Medium

Base Score: 6.9

Threat Score: 2.7

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Vulnerability Information

Exploit Ease: No known exploits are available

Patch Publication Date: 5/21/2026

Vulnerability Publication Date: 5/20/2026

Reference Information

CVE: CVE-2026-44390