Answer in brief
CVE-2026-101338 records a High severity (CVSS 8.7) vulnerability in Stack overwrite from a specially crafted and formatted SVCB or HTTPS RR. The current sources do not mark it as known exploited. The current feed maps NLnet Labs/NSD (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps NLnet Labs/NSD (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| NLnet Labs/NSDgeneric | >=4.10.0 <4.15.3 | 4.15.3 |
Published upstream
Oct 14, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 14, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 14, 2026
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).
Quoted source text, attributed separately from HOL analysis.