CVE-2026-80225: nlnet labs unbound
Vulnerability summary
CVE-2026-80225 is a high (CVSS 7.5) vulnerability in nlnet labs unbound. EPSS estimates a 0.48% chance of exploitation in the next 30 days, higher than 40.2% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 8 · Related 6Timeline
- 16-09-2026PublishedVulnerability first disclosed.
- 16-09-2026Last modifiedVulnerability information updated.
Description
In NLnetLabs Unbound up to and including 1.26.0, a degradation of service vulnerability is present in the TCP/DoT reading procedure where there is no limit on consecutive reads. A malicious actor that can stream and sustain a rate of distinct uncached names over the TCP/DoT connection, monopolizes a single worker's entire event loop for as long as its writes stay ahead of the drain.
CVSS metrics
4 scores · 4 sources · 1 version- CVE.orgCNA5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:LDiffers
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.48%
Chance of exploitation in the next 30 days
Percentile
40%
Versus all other CVEs
30-day change
+0.17 pp
From 0.31% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Debian1 product
- unboundAll versions (No fix recorded) | < 1.26.1-0+deb13u1 | < 1.26.1-1
Nlnet labs1 product
- unbound< 1.26.1
Nlnetlabs1 product
- unbound< 1.26.1
Ubuntu1 product
- unboundAll versions (No fix recorded)
4 vendors · 4 products
