How severe is CVE-2026-12246?

CVE-2026-12246 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.

Is CVE-2026-12246 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-12246?

CVE-2026-12246 affects Nlnetlabs Nsd. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-12246?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-12246 have an EU (EUVD) identifier?

Yes. CVE-2026-12246 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-39184.

When was CVE-2026-12246 published?

CVE-2026-12246 was published on 2026-06-25 and last updated on 2026-06-26.

CVE-2026-12246

CVE-2026-12246 is a high-severity vulnerability in Nlnetlabs Nsd with a CVSS 3.x base score of 8.1. 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-20.

Key facts

Severity: High (CVSS 3.x base score 8.1)
CVSS v4: 7.2
EPSS exploit prediction: 0% (18th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-39184
Weakness: CWE-20
Affected product: Nlnetlabs Nsd
Published: 2026-06-25
Last modified: 2026-06-26

Description

NSD version 4.14.0 introduced a bug where a specially crafted APL RR, with an adflength larger than permitted for the address family will overwrite the stack when the zone is written to disk, with a maximum of 111 attacker controlled bytes.

Frequently asked questions

What is CVE-2026-12246?: NSD version 4.14.0 introduced a bug where a specially crafted APL RR, with an adflength larger than permitted for the address family will overwrite the stack when the zone is written to disk, with a maximum of 111 attacker controlled bytes.
How severe is CVE-2026-12246?: CVE-2026-12246 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
Is CVE-2026-12246 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-12246?: CVE-2026-12246 affects Nlnetlabs Nsd. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-12246?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-12246 have an EU (EUVD) identifier?: Yes. CVE-2026-12246 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-39184.
When was CVE-2026-12246 published?: CVE-2026-12246 was published on 2026-06-25 and last updated on 2026-06-26.

References

https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-12246.txt

Affected products (1)

cpe:2.3:a:nlnetlabs:nsd:*:*:*:*:*:*:*:*

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