Long list of incoming EDNS options degrades performance (NLnet Labs Unbound)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.75 % · percentile 55 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- NLnet Labs
- NVD status
- Modified
Description
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).
Weaknesses (CWE)
- CWE-407 — Inefficient Algorithmic Complexity
- CWE-770 — Allocation of Resources Without Limits or Throttling
- CWE-1050 — Excessive Platform Resource Consumption within a Loop
References
- https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-41292.txt
- https://access.redhat.com/security/cve/CVE-2026-41292
- https://bugzilla.redhat.com/show_bug.cgi?id=2480125
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-41292.json
- https://access.redhat.com/errata/RHSA-2026:54769
- https://access.redhat.com/errata/RHSA-2026:36320
- https://access.redhat.com/errata/RHSA-2026:37282
- https://access.redhat.com/errata/RHSA-2026:36777
- https://access.redhat.com/errata/RHSA-2026:24013
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 4.0 | MEDIUM 6.6 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Red | NLnet Labs |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | redhat-SADP |
| CVSS 4.0 | MEDIUM 6.6 | CVSS:4.0/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 | NVD · sep@nlnetlabs.nl (Secondary) |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD · nvd@nist.gov (Primary) |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c (Secondary) |
European references
- ENISA EUVD · EUVD-2026-31078
- GCVE · GCVE-0-2026-41292
Affected configurations (NVD CPE)
cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*< 1.25.1
Affected products
| Product | Versions |
|---|---|
| NLnet Labs · Unbound | affected 0 < 1.25.1 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |