CVE-2026-41292: Long list of incoming EDNS options degrades performance
Last updated 2 June 2026
Other sources
Long list of incoming EDNS options degrades performance
— Microsoft
NLnet Labs Unbound up to and including version 1.25.0 is vulnerable to a degradation of service attack related to parsing long lists of incoming EDNS options. An adversary sending queries with too many EDNS options can hold Unbound threads hostage while they are parsing and creating internal data structures for the options. Coordinated attacks can result in degradation and/or denial of service. Unbound 1.25.1 contains a patch with a fix to limit acceptable incoming EDNS options (100).
— Launchpad
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/unboundto a version that resolves this vulnerability.Fixed in 1.22.0-2+deb13u3Fixed in 1.25.1-1 - Upgrade
Upgrade
NLnet Labs Unboundto a version that resolves this vulnerability.Fixed in 1.25.1
Event History
Frequently Asked Questions
What is the severity of CVE-2026-41292?
CVE-2026-41292 is classified as a vulnerability that can cause degradation of service in NLnet Labs Unbound.
How do I fix CVE-2026-41292?
To mitigate CVE-2026-41292, upgrade NLnet Labs Unbound to a version later than 1.25.0.
What impact does CVE-2026-41292 have on performance?
CVE-2026-41292 can severely degrade performance by overwhelming Unbound with excessive incoming EDNS options.
Who is affected by CVE-2026-41292?
CVE-2026-41292 affects users running NLnet Labs Unbound version 1.25.0 or earlier.
What type of attack is associated with CVE-2026-41292?
CVE-2026-41292 is associated with a degradation of service attack caused by malicious queries with long EDNS option lists.