TI-2026-55459 Aliases CVE-2026-80225 GHSA-8wrv-pfvg-j383

Possible degradation of service from continuous queries on the same TCP/DoT connection

LOW 39CWE-770Published 2026-09-16 · Updated 2026-09-16

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: Partial Red Hat: 1 fixed, 7 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-770.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00482 41st percentileScored 2026-11-07

Fix Partial Unbound (NLnet Labs): 1.26.1Red Hat: 1 advisoryRed Hat: 1 fixed, 7 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
NLnet Labs	Unbound	before 1.26.1	1.26.1	Patch available	CNA

Unbound VendorNLnet Labs Affected before 1.26.1 Fixed in 1.26.1 Patch available CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:nlnetlabs:unbound::::::::	before 1.26.1	Vulnerable	NLNETLABS

cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:* Versions before 1.26.1 Vulnerable ·NLNETLABS

Remediation

Fix · CNA Unbound (NLnet Labs) Fixed in 1.26.1

Red Hat 1 advisory

RHSA-2026:68590 Released 2026-09-17 · Red Hat rating Critical
Red Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images python3-unbound-1.26.1-1.hum1@aarch64, python3-unbound-1.26.1-1.hum1@x86_64, unbound-1.26.1-1.hum1@aarch64 +14

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

Release · 2026-09-16
NLnet Labs Unbound 1.26.1
9 records Highest priority Priority MEDIUM 2 MEDIUM, 7 LOW
Other records, highest priority first
- TI-2026-56302 Heap buffer overflow and possible Remote Code Execution when digesting DNSKEYPriority MEDIUM 49
- TI-2026-57038 CNAME synthesis could lead to heap corruptionPriority MEDIUM 40
- TI-2026-58665 Retrap: Novel Vulnerabilities to launch Algorithmic Complexity Attacks on DNSSECPriority LOW 39
Show all 9 records →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Product	Status	Plan or fix
Red Hat Enterprise Linux 10	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 6	Affected	No fix planned: Out of support scope
Red Hat Enterprise Linux 7	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 8	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 9	Affected	No fix yet: Fix deferred
Red Hat OpenShift Container Platform 4	Affected	No fix yet: Fix deferred
Red Hat OpenShift Container Platform 5	Affected	No fix yet: Fix deferred
Red Hat Hardened Images	Fixed	RHSA-2026:68590

Timeline

2026-10-02 Threatist record created from CVE-2026-80225
2026-10-03 Alias added: GHSA-8wrv-pfvg-j383
2026-11-06 Affected versions changed · Red Hat

References

Patch 1

https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-80225.txt

TI-2026-25690 Possible arbitrary code execution during DNSSEC validation CVSS 4.0CRITICAL 9.1
TI-2026-56302 Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY CVSS 4.0CRITICAL 9.1
TI-2026-31146 Crash during DNSSEC validation of malicious content CVSS 4.0HIGH 8.7
TI-2026-31135 Heap overflow with multiple NSID, COOKIE, PADDING EDNS options CVSS 4.0HIGH 8.7
TI-2026-36436 Routinator crashes on specifically crafted RRDP XML files CVSS 4.0HIGH 8.7
TI-2026-36433 Routinator exits when accepting an incoming HTTP or RTR connection fails CVSS 4.0HIGH 8.7

See all 96 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences