MediumCVE-2026-126814

blueprintUE Self-Hosted Edition before 4.3.6 Arbitrary Iframe Embedding via PeerTube Matcher (CVE-2026-126814)

Published 11.11.2026Last modified 11.11.2026Sources: EUVD, CVE.org

What is affected, what to do

blueprintUE Self-Hosted Edition before 4.3.6 contains an iframe injection vulnerability that allows authenticated users to embed arbitrary third-party content by abusing the PeerTube video URL matcher in BlueprintService::findVideoProvider(). Attackers can set a blueprint video URL on an attacker-controlled host, which site.js loads in an unsandboxed iframe after consent, framing fake login forms or malware downloads.

Update Blueprintue-self-hosted-edition to version 4.3.6.

Affected: Blueprintue-self-hosted-edition lt 1.0.0..4.3.6
Fixed in: Blueprintue-self-hosted-edition 4.3.6

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Metrics

4.8

XIEM Effective CVSS

Highest available CVSS rating from NVD and vendor data.

Source: Vendor (CNA), CVSS v4

3.5

CVSS v3

Severity Low on the scale from 0 to 10.

Source: EUVD, CVE.org

0.3 %

EPSS score

Low — model estimates < 1% exploitation likelihood.

Source: FIRST EPSS, percentile 17.5

Show all metrics

Severity: Medium
Priority (0–325) The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first? Read in glossary: 56.45 Methodology
Exploit maturity An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack. Read in glossary: no public PoC known
XIEM Effective CVSS XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command. Read in glossary: 4.8 Methodology
CVSS v3 CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions. Read in glossary: 3.5
CVSS v4 CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions. Read in glossary: 4.8
EPSS score The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“. Read in glossary: 0.3 %; Low — model estimates < 1% exploitation likelihood.
EPSS percentile The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking. Read in glossary: 17.5; Elevated — this CVE ranks above at least 10% of all CVEs scored today.
KEV status The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching. Read in glossary: —
Published: 11.11.2026
CWE CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect. Read in glossary: CWE-829

Detection rules

No NEOSEC detection rule is available for this vulnerability yet.

Classification under NIS2 and CRA

Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

NIS2 NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management. Read in glossary: Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
CRA The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates. Read in glossary: From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001 ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security. Read in glossary: Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

Description

Source: ENISA EUVD, NVD (NIST), cvelistv5, CVE.org (MITRE)

Affected products

The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

Affected products
		Affected versions	Fixed in
blueprintue	blueprintue-self-hosted-edition	`1.0.0 – < 4.3.6`	`4.3.6`

Vendors and products

Blueprintue Blueprintue-self-hosted-edition

Weakness classes (CWE)

CWE-829Inclusion of Functionality from Untrusted Control Sphere
Base
The product imports, requires, or includes executable functionality (such as a library) from a source that is outside of the intended control sphere.
Entry at MITRE CWE-829

References & sources

github.comblueprintue/blueprintue-self-hosted-edition/blob/v4.3.5/app/ser…Technical description, euvd
github.comblueprintue/blueprintue-self-hosted-edition/commit/5f13e2bb8cd4…Patch, euvd
github.comblueprintue/blueprintue-self-hosted-edition/pull/269Issue tracking, Patch, euvd
github.comblueprintue-self-hosted-edition v4.3.6 Release NotesRelease notes, euvd
github.comGitHub Security Advisory (GHSA-3vgc-fcfg-v233)Vendor advisory, euvd
vulncheck.comVulnCheck Advisory: blueprintUE Self-Hosted Edition before 4.3.6 Arbitrary Iframe Embedding via PeerTube MatcherThird-party advisory, euvd
NVD (NIST)vuln/detail/CVE-2026-126814euvd

Changes to this CVE

Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

11.11.2026ReceivedVulnCheck

CVSS V4.0: AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

CVSS V3.1: AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N

Weakness type: CWE-829

Description added or changed

New references:

and 2 more references

Show 11 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Description	added	—	blueprintUE Self-Hosted Edition before 4.3.6 contains an iframe injection vulnerability that allows authenticated users to embed arbitrary third-party content by abusing the PeerTube video URL matcher in BlueprintService::findVideoProvider(). Attackers can set a blueprint video URL on an attacker-controlled host, which site.js loads in an unsandboxed iframe after consent, framing fake login forms or malware downloads.
CVSS	added	—	AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:L/VA:N/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
CVSS	added	—	AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
Weakness type (CWE)	added	—	CWE-829
Affected versions (publisher)	added	—	New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/126xxx/CVE-2026-126814.json">CVE-2026-126814</a>
Reference	added	—	https://github.com/blueprintue/blueprintue-self-hosted-edition/blob/v4.3.5/app/services/www/BlueprintService.php#L700-L716
Reference	added	—	https://github.com/blueprintue/blueprintue-self-hosted-edition/commit/5f13e2bb8cd4c620899e9f8afd41a6e62b3bc6a4
Reference	added	—	https://github.com/blueprintue/blueprintue-self-hosted-edition/pull/269
Reference	added	—	https://github.com/blueprintue/blueprintue-self-hosted-edition/releases/tag/v4.3.6
Reference	added	—	https://github.com/blueprintue/blueprintue-self-hosted-edition/security/advisories/GHSA-3vgc-fcfg-v233
Reference	added	—	https://www.vulncheck.com/advisories/blueprintue-self-hosted-edition-before-4.3.6-arbitrary-iframe-embedding-via-peertube-matcher

Source identifier: disclosure@vulncheck.com

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