CVE-2026-101338
8.7HighPublished 14 Oct 2026 · NVD status: Awaiting Analysis · AI triage by gemini-3.8-flash
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Impact
- Full C/I/A compromise
- Weakness
- CWE-121
Impact
Attackers with zone provisioning access can achieve remote code execution or crash the NSD daemon. They need the ability to supply or push a maliciously crafted zone file directly to the NSD instance.
Root cause
A stack-based buffer overflow in the SVCB/HTTPS resource record parser allows an overflowing ECH parameter to write arbitrary base64-decoded data past stack boundaries.
Affected systems
Versions not listed — check the vendor advisory.
CVSS v4.0 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/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
Fix & remediation
Upgrade NSD to the patched release referenced in the NLnet Labs advisory. As an interim workaround, sanitize incoming zone files or block unvalidated SVCB/HTTPS records with oversized ECH parameters from entering provisioning pipelines.
AI-suggested. Run it in staging first and check it against the vendor advisory. Why?
NVD description
When a SVCB or HTTPS RR has filled the wire format RDATA up to the brim, another ECH parameter may overwrite the stack, and once beyond the limit, the base64 decoder can write attacker controlled data of unlimited size. Zone files which are written out by NSD itself, such as for zones for which the NSD instance is secondary, will not be formatted like this. The zone file must be fed to NSD directly, (but it could come, for example, from an operator controlled provisioning system).