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.
References
| Link | Resource |
|---|---|
| https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-32792.txt | Mitigation Vendor Advisory |
Configurations
History
20 May 2026, 22:44
| Type | Values Removed | Values Added |
|---|---|---|
| First Time |
Nlnetlabs
Nlnetlabs unbound |
|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 5.3 |
| References | () https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-32792.txt - Mitigation, Vendor Advisory | |
| CPE | cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:* |
20 May 2026, 10:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-05-20 10:16
Updated : 2026-05-20 22:44
NVD link : CVE-2026-32792
Mitre link : CVE-2026-32792
CVE.ORG link : CVE-2026-32792
JSON object : View
Products Affected
nlnetlabs
- unbound