How severe is CVE-2026-50248?

CVE-2026-50248 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability low.

Is CVE-2026-50248 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-50248?

CVE-2026-50248 affects Nlnetlabs Unbound. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-50248?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2026-50248 published?

CVE-2026-50248 was published on 2026-07-22 and last updated on 2026-07-24.

CVE-2026-50248

CVE-2026-50248 is a medium-severity vulnerability in Nlnetlabs Unbound with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-345.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 0% (3rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-345
Affected product: Nlnetlabs Unbound
Published: 2026-07-22
Last modified: 2026-07-24

Description

In NLnet Labs Unbound 1.7.0 up to and including 1.25.1, when an auth/rpz zone has a configured primary hostname that resolves to BOGUS A/AAAA, it is still considered as a possible XFR endpoint. A malicious actor that can spoof the hostname's A/AAAA record (no valid RRSIG required) becomes the zone's XFR primary and can replaces the entire zone/the resolver's entire response policy.

Frequently asked questions

What is CVE-2026-50248?: In NLnet Labs Unbound 1.7.0 up to and including 1.25.1, when an auth/rpz zone has a configured primary hostname that resolves to BOGUS A/AAAA, it is still considered as a possible XFR endpoint. A malicious actor that can spoof the hostname's A/AAAA record (no valid RRSIG required) becomes the zone's XFR primary and can replaces the entire zone/the resolver's entire response policy.
How severe is CVE-2026-50248?: CVE-2026-50248 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability low.
Is CVE-2026-50248 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-50248?: CVE-2026-50248 affects Nlnetlabs Unbound. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-50248?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-50248 published?: CVE-2026-50248 was published on 2026-07-22 and last updated on 2026-07-24.

References

https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-50248.txt

Affected products (1)

cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*

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