Vulnerability · Published Jul 22, 2026 · Assigned by NLnet Labs

CVE-2026-50045'max-global-quota' reset by DNSSEC validation restarts

Medium 5.3

In plain English

A medium-severity security flaw in Unbound from NLnet Labs. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.3Medium

Exploit odds (30 days)0.5%top 59.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, a single client query for a deeply nested name under a DNSSEC-signed parent can cause Unbound to send more upstream packets per client query than the configured 'max-global-quota'. This effectively bypasses a security configuration that limits upstream amplification traffic.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Alpine:v3.22	unbound	1.25.2-r0	ALPINE-CVE-2026-50045
Alpine:v3.23	unbound	1.25.2-r0	ALPINE-CVE-2026-50045
Alpine:v3.24	unbound	1.25.2-r0	ALPINE-CVE-2026-50045
Debian:12	unbound	no fix listed	DEBIAN-CVE-2026-50045
Debian:13	unbound	1.26.1-0+deb13u1	DEBIAN-CVE-2026-50045
Debian:14	unbound	1.25.2-1	DEBIAN-CVE-2026-50045
Ubuntu:22.04:LTS	unbound	no fix listed	UBUNTU-CVE-2026-50045
Ubuntu:24.04:LTS	unbound	no fix listed	UBUNTU-CVE-2026-50045
Ubuntu:26.04:LTS	unbound	no fix listed	UBUNTU-CVE-2026-50045
Ubuntu:26.10	unbound	no fix listed	UBUNTU-CVE-2026-50045

Affected products (as reported)

Vendor	Product	Versions
NLnet Labs	Unbound	1.22.0 – before 1.25.2

Weakness: CWE-406 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References

https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-50045.txt vendor-advisory