Service Degradation Vulnerability in NLnet Labs Unbound Product
CVE-2026-41292

6.6MEDIUM

Key Information:

Vendor

Nlnet Labs

Status
Unbound
Vendor
CVE Published:
20 May 2026

What is CVE-2026-41292?

NLnet Labs Unbound, prior to version 1.25.1, is susceptible to a service degradation issue stemming from the handling of overly extensive EDNS options. When an attacker submits queries containing a multitude of EDNS options, it may cause the Unbound threads to become overwhelmed and unable to process incoming requests effectively. This scenario can lead to a significant slowdown in service or an outright denial of service if managed through coordinated attacks. A patch included in version 1.25.1 restricts the number of acceptable incoming EDNS options to 100, thereby mitigating this risk.

Affected Version(s)

Unbound 0 < 1.25.1

References

https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-41292...
vendor-advisory

CVSS V4

Score:
6.6
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

GitHub user N0zoM1z0
Qifan Zhang (Palo Alto Networks)
.