CVE-2026-50045: unbound — Fix

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.

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CVSS v3.1 Score

5.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS — Exploit Prediction

0.0028

Probability of exploitation

0.20%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-406 CWE-406

Affected Products

Vendor	Product	Versions
nlnetlabs	unbound	1.22.0 — 1.25.2

References

Advisories & Patches

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

Frequently Asked Questions

What is CVE-2026-50045? +

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. It has a CVSS v3.1 base score of 5.3 (MEDIUM).

How severe is CVE-2026-50045? +

CVE-2026-50045 has a CVSS v3.1 score of 5.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0028, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-50045? +

CVE-2026-50045 affects products from nlnetlabs, specifically: unbound. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-50045? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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