CVE-2026-32792
Packet of death with DNSCrypt
Description
NLnet Labs Unbound 1.6.2 up to and including version 1.25.0 has a denial of service vulnerability when compiled with DNSCrypt support ('--enable-dnscrypt'). A bad DNSCrypt query could underflow Unbound's DNSCrypt packet reading procedure that may lead to heap overflow. A malicious actor can exploit the vulnerability with a single bad DNSCrypt query that its decrypted plaintext consists entirely of '0x00' bytes and does not contain the expected '0x80' marker. Unbound would then start reading more bytes than necessary until it finds a non-'0x00' byte. Based on the underlying memory allocator and the memory layout, it could lead to heap overflow while reading followed by a crash. Likelihood of a crash is low, since it relies heavily on the underlying memory allocator and the memory layout. If the heap overflow does not happen, Unbound's later packet checks will deny the packet. Unbound 1.25.1 contains a patch with a fix to bound reading in the given buffer space.
INFO
Published Date :
May 20, 2026, 10:16 a.m.
Last Modified :
July 24, 2026, 10:10 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | MEDIUM | 206fc3a0-e175-490b-9eaa-a5738056c9f6 | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update Unbound to version 1.25.1.
- Ensure DNSCrypt support is configured correctly.
- Monitor system stability after update.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-32792.
| URL | Resource |
|---|---|
| https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-32792.txt | Mitigation Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-32792 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-32792
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-32792 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-32792 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Jul. 24, 2026
Action Type Old Value New Value Added Translation Title: Unbound de NLnet Labs, Description: NLnet Labs Unbound 1.6.2 hasta e incluyendo la versión 1.25.0 tiene una vulnerabilidad de denegación de servicio cuando se compila con soporte para DNSCrypt ('--enable-dnscrypt'). Una consulta DNSCrypt incorrecta podría causar un underflow en el procedimiento de lectura de paquetes DNSCrypt de Unbound que puede llevar a un desbordamiento de montículo. Un actor malicioso puede explotar la vulnerabilidad con una única consulta DNSCrypt incorrecta cuyo texto plano descifrado consiste enteramente en bytes '0x00' y no contiene el marcador '0x80' esperado. Unbound entonces comenzaría a leer más bytes de los necesarios hasta que encuentre un byte que no sea '0x00'. Basado en el asignador de memoria subyacente y la disposición de la memoria, podría llevar a un desbordamiento de montículo durante la lectura seguido de un fallo. La probabilidad de un fallo es baja, ya que depende en gran medida del asignador de memoria subyacente y de la disposición de la memoria. Si el desbordamiento de montículo no ocurre, las comprobaciones posteriores de paquetes de Unbound denegarán el paquete. Unbound 1.25.1 contiene un parche con una corrección para limitar la lectura en el espacio de búfer dado. -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'NLnet Labs', 'product': 'Unbound', 'versions': [{'status': 'affected', 'version': '1.6.2', 'lessThan': '1.25.1', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-32792', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-05-20T12:15:56.617664Z'} -
Initial Analysis by [email protected]
May. 20, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Added CPE Configuration OR *cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:* versions from (including) 1.6.2 up to (excluding) 1.25.1 Added Reference Type NLnet Labs: https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-32792.txt Types: Mitigation, Vendor Advisory -
New CVE Received by [email protected]
May. 20, 2026
Action Type Old Value New Value Added Description NLnet Labs Unbound 1.6.2 up to and including version 1.25.0 has a denial of service vulnerability when compiled with DNSCrypt support ('--enable-dnscrypt'). A bad DNSCrypt query could underflow Unbound's DNSCrypt packet reading procedure that may lead to heap overflow. A malicious actor can exploit the vulnerability with a single bad DNSCrypt query that its decrypted plaintext consists entirely of '0x00' bytes and does not contain the expected '0x80' marker. Unbound would then start reading more bytes than necessary until it finds a non-'0x00' byte. Based on the underlying memory allocator and the memory layout, it could lead to heap overflow while reading followed by a crash. Likelihood of a crash is low, since it relies heavily on the underlying memory allocator and the memory layout. If the heap overflow does not happen, Unbound's later packet checks will deny the packet. Unbound 1.25.1 contains a patch with a fix to bound reading in the given buffer space. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Green Added CWE CWE-125 Added CWE CWE-166 Added Reference https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-32792.txt