EUVD-2026-39184
GHSA-xgm5-85mh-3559
Severity by source
CVSS: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
Attacker must control zone content so PR:L; network-reachable serialization path AV:N/AC:L; stack overwrite corrupts/crashes giving I:H and A:H with no disclosure (C:N).
Primary rating from Vendor (NLnet Labs).
CVSS VectorVendor: NLnet Labs
CVSS: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
Lifecycle Timeline
2DescriptionCVE.org
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.
AnalysisAI
Stack buffer overflow in NSD 4.14.0 (NLnet Labs authoritative DNS server) allows a party able to introduce zone data to overwrite up to 111 attacker-controlled bytes on the stack when a specially crafted APL resource record - carrying an adflength larger than the address family permits - is serialized as the zone is written to disk. Per the CVSS 4.0 vector (PR:L), exploitation requires low privileges and yields high integrity and availability impact, consistent with memory corruption leading to crash or potential code execution. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the attacker to get a malformed APL (Address Prefix List) resource record - one whose afdlength exceeds the maximum permitted for its declared address family - accepted into a zone that NSD 4.14.0 serves, and the overflow triggers specifically when that zone is written to disk. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | Signals are moderately consistent rather than alarming. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker who can influence the contents of a zone served by NSD 4.14.0 - for example a malicious or compromised primary feeding a secondary, or an actor able to inject records through a zone-management interface - crafts an APL resource record with an afdlength larger than its address family permits. When NSD writes that zone to disk, the oversized address data overflows a stack buffer with up to 111 attacker-controlled bytes, crashing the daemon or potentially corrupting the stack toward code execution. … |
| Remediation | Upgrade NSD to the fixed release published by NLnet Labs as referenced in the advisory at https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-12246.txt; the input data does not contain a confirmed exact fix version, so released patched version is not independently confirmed and the precise target version should be read from that advisory before deploying. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
24 hours: Identify all systems running NSD 4.14.0 and audit zone data update sources (automated scripts, APIs, manual imports). …
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Remote denial-of-service in NLnet Labs NSD (authoritative DNS name server) version 4.13.0 and later allows an unauthenti
Heap overflow in NLnet Labs NSD allows a malicious or compromised zone primary to corrupt memory on a secondary (slave)
Zone-transfer authentication bypass in NLnet Labs NSD allows unauthorized secondaries to obtain full zone contents witho
NSD before 4.1.11 allows remote DNS master servers to cause a denial of service (/tmp disk consumption and slave server
query.c in NSD 3.0.x through 3.0.8, 3.1.x through 3.1.1, and 3.2.x before 3.2.12 allows remote attackers to cause a deni
Same weakness CWE-120 – Classic Buffer Overflow
View allSame technique Buffer Overflow
View allVendor StatusVendor
SUSE
Severity: ImportantShare
External POC / Exploit Code
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