Detections
Analytics

Echo: unbound: security update to 1.26.1

medium Tenable Self-Hosted Container Security Plugin ID 459268

Description

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

 - NLnet Labs Unbound 1.22.0 up to and including 1.26.1, has a use-after-free vulnerability when compiled for
 DNS-over-QUIC support with '--with-libngtcp2'. Each DoQ stream owns an output buffer that holds the DNS
 response. ngtcp2's retransmission buffer keeps a shallow pointer into the output buffer for as long as a
 STREAM frame may be resent. On a client RESET_STREAM, the output buffer is freed but ngtcp2 still holds
 the matching retransmission entries. The next PTO timeout makes ngtcp2 re-encode the STREAM frame and copy
 from the freed buffer. A malicious actor that can query Unbound over DoQ and that withholds ACKs, sends
 RESET_STREAM, and waits for PTO, reaches this use-after-free with no privilege. This leads to
 retransmissions against freed memory and eventually an abnormal server exit under a 20-query spray.
 (CVE-2026-78227)

Solution

Update the unbound library and its related packages to version 1.26.1 or later.

See Also

https://advisory.echohq.com/cve/CVE-2026-78227

Plugin Details

Severity: Medium

ID: 459268

Version: Revision 1.1

Type: Local

Published: 10/2/2026

Updated: 10/2/2026

Risk Information

VPR

Risk Factor: Medium

Score: 5.5

Percentile: 95.89

CVSS v2

Risk Factor: Medium

Base Score: 6.1

Temporal Score: 4.5

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

CVSS Score Source: CVE-2026-78227

CVSS v3

Risk Factor: Medium

Base Score: 6.5

Temporal Score: 5.7

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/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: 9/16/2026

Vulnerability Publication Date: 9/16/2026

Reference Information

CVE: CVE-2026-78227