CVE-2026-82717

In NLnet Labs Unbound up to and including 1.26.0, a vulnerability was found in that can progressively corrupt heap memory and under certain systems and compilation options could lead to remote code execution. The vulnerability starts when CNAME synthesis during an upstream response needs to enforce(rewrite) a max TTL value in the packet buffer. Coupled with a compression pointer that points to the overwritten value and invalidates the domain name, it leads to an error path that does not properly move the buffer position and allows for the heap buffer overflow. Since this is heavily reliant on heap memory layout, results are memory corruption that eventually leads to a crash and under specific systems and compilation options remote code execution.

CVSS v3 9.8 CRITICAL

9.8^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-82717.txt	Patch Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*

History

23 Sep 2026, 19:50

Type	Values Removed	Values Added
References	~~() https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-82717.txt -~~	() https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-82717.txt - Patch, Vendor Advisory
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 9.8
CPE		cpe:2.3:a:nlnetlabs:unbound::::::::
First Time		Nlnetlabs Nlnetlabs unbound

Information

Published : 2026-09-16 09:17

Updated : 2026-09-23 19:50

NVD link : CVE-2026-82717

Mitre link : CVE-2026-82717

CVE.ORG link : CVE-2026-82717

JSON object : View

Products Affected

nlnetlabs

unbound

CWE

CWE-122

Heap-based Buffer Overflow

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