CVE-2026-101338

Stack overwrite from a specially crafted and formatted SVCB or HTTPS RR

CVSS score

8.7

EPSS probability

—

Risk score

0.9

Published

14 h ago

Overview Public Exploits (0)Newsroom Vulnerability Timeline

Patch status has not yet been verified

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Impact on My Inventory

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Vulnerability description

CVE AI research

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DayBreach AI Explanation

Verified against sources

NLnet Labs NSD SVCB or HTTPS RR Stack Overwrite Vulnerability

Sources read

Source agreement

Tam uyum

Evidence confidence

%63

Short explanation

A stack overwrite vulnerability exists in NLnet Labs NSD when processing SVCB or HTTPS resource records [S0, S1]. The vulnerability allows attackers with low privileges over the network to impact confidentiality, integrity, and availability [S0, S1]. The patch status remains unverified in official sources [S0].

Why does it matter?

This security flaw enables authenticated users with network access to perform stack overwrites [S0, S1]. Attackers can exploit this issue to create high severity impacts across confidentiality, integrity, and availability [S0, S1].

What should be done?

Follow vendor advisories [S0]
Audit zone file provisioning processes [S0, S1]
Consider the uncertain patch status carefully [S0]

Chain of evidence and sources3 verified claims

NLnet Labs NSD 4.10.0 ile 4.15.3 sürümleri arasındaki ürünler etkilenmektedir.

S0 · daybreach-canonical S1 · cvelist

Zafiyetin CVSS taban puanı 8.7 olarak belirlenmiştir.

S0 · daybreach-canonical S1 · cvelist

Yama durumu resmi kaynaklarda doğrulanamamıştır.

S0 · daybreach-canonical

Show the technical text from the sources

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).

CVSS vector: 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

CWE: CWE-121

Explanation produced with the local gemini-flash-lite-latest model. Numerical metrics and the KEV, patch and exploit statuses are not determined by AI.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-101338 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

ID	VENDOR	PRODUCT	ACTION
1	NLnet Labs	NSD	View

Total affected vendors: 1|Products: 1

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCORE	VERSION	SEVERITY	VECTOR	SOURCE
8.7	CVSS V4_0	HIGH	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	CVE CNA
8.7	CVSS V40	HIGH	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	NVD

Patch and Remediation Guide

Solution & Remediation Advisory

Patch status unknown

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Confirm the affected product and version against the source evidence above.

Restrict access to internet-facing services and apply network segmentation.

Until a patch is confirmed, follow the vendor advisory; do not read an unknown status as “no patch”.

Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-101338 is associated with the following CWEs:

CWE-121: Common Weakness Enumeration Entry CWE-121

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-101338 weaknesses.

CAPEC-66: SQL Injection CAPEC-126: Path Traversal CAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden

PermissionsLow

UserGerekmiyor

Official Sources and Advisories

https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-101338.txtvendor-advisory

CVSS Vector Radar Chart

8.7 / 10

Vulnerability Scoring Details

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

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow privileges

User InteractionNone required

Confidentiality (Gizlilik)Low

Integrity (Bütünlük)None

Availability (Erişilebilirlik)High

Yama durumu bilinmiyor

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Follow the vendor

NLnet Labs

Weakness Type (CWE & CAPEC)

CWE-121

Similar Vulnerabilities

8.7

CVE-2026-101341

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