PT-2026-42128 · Nlnet · Unbound

Qifan Zhang · Published 2026-05-20 · Updated 2026-05-20 · CVE-2026-41292

NVD

CVSS v4.0

6.6

Medium

Base vector

AV:N/AC:L/AT:N/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:Red

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).

Fix

Allocation of Resources Without Limits

Weakness Enumeration

CWE-407

CWE-770

Related Identifiers

CVE-2026-41292

Affected Products

Unbound

References · 4

• https://nvd.nist.gov/vuln/detail/CVE-2026-41292 · Security Note
• https://nlnetlabs.nl/downloads/unbound/CVE-2026-41292.txt · Vendor Advisory
• https://twitter.com/OrangeMorishita/status/2057047743336681799 · Twitter Post
• https://twitter.com/OrangeMorishita/status/2057047822378455523 · Twitter Post