CVE-2026-12246: nlnet labs nsd Improper Input Validation
CVSS: 8.1v3.1HighAnalyzed
AliasesALPINE-CVE-2026-12246UBUNTU-CVE-2026-12246DEBIAN-CVE-2026-12246
Published 25-06-2026Last modified 25-06-2026
Vulnerability summary
CVE-2026-12246 is a high (CVSS 8.1) Improper Input Validation vulnerability in nlnet labs nsd. EPSS estimates a 0.44% chance of exploitation in the next 30 days, higher than 37.2% of scored vulnerabilities.
CVSS score
8.1/10
010
High · v3.1 (NVD)EPSS score
0.44%
0%100%
Low · +0.14 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 2 · Related 3Timeline
- 25-06-2026PublishedVulnerability first disclosed.
- 25-06-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
7 scores · 5 sources · 2 versionsHigh 7.2Preferred score · CVE.org (CNA)
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:NSourcesAll 3 agree
- OSV · UbuntuEcosystem advisory · calculated7.2HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
- NVDNIST7.2HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
High 8.1Preferred score · NVD (NIST)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:HSourcesAll 4 agree
- OSV · AlpineEcosystem advisory · calculated8.1HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
- OSV · UbuntuEcosystem advisory · calculated8.1HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
- OSV · DebianEcosystem advisory · calculated8.1HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
EPSS trend
Probability
0.44%
Chance of exploitation in the next 30 days
Percentile
37%
Versus all other CVEs
30-day change
+0.14 pp
From 0.30% on 19-09-2026
19-09-202619-10-2026
EPSS score0.44%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-20Improper Input ValidationThe product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
- CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.
Affected systems
Alpine1 product
- nsd≥ 4.14.0, < 4.14.3-r0
Debian1 product
- nsd< 4.14.3-1
Nlnet labs1 product
- nsd≥ 4.14.0, < 4.14.3
Nlnetlabs1 product
- nsd≥ 4.14.0, < 4.14.3
Ubuntu1 product
- nsd< 4.1.7-1ubuntu0.1~esm1 | < 4.1.17-1ubuntu0.1~esm1 | < 4.1.26-1ubuntu0.1~esm1 | < 4.3.9-1ubuntu0.1~esm1 | < 4.8.0-1ubuntu0.1~esm1 | All versions (No fix recorded) | < 4.14.0-1ubuntu0.1~esm1
5 vendors · 5 products
