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Vulnerability details: VCID-tgrp-u3wm-s3cb
Vulnerability ID VCID-tgrp-u3wm-s3cb
Aliases CVE-2021-34435
GHSA-v9w2-v7j9-rjpr
Summary Exposure of Resource to Wrong Sphere In Eclipse Theia to, the mini-browser extension allows a user to preview HTML files in an iframe inside the IDE. But with the way it is made it is possible for a previewed HTML file to trigger an RCE. This exploit only happens if a user previews a malicious file.
Status Published
Exploitability 0.5
Weighted Severity 8.0
Risk 4.0
Affected and Fixed Packages Package Details
Weaknesses (5)
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Found at https://bugs.eclipse.org/bugs/show_bug.cgi?id=568018
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Found at https://github.com/eclipse-theia/theia
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Found at https://github.com/eclipse-theia/theia/commit/0761dcf5fe3c14c27432683d42d2c526ad0cfbd5
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Found at https://github.com/eclipse-theia/theia/pull/8759
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Found at https://nvd.nist.gov/vuln/detail/CVE-2021-34435
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none

Exploit Prediction Scoring System (EPSS)
Percentile 0.30922
EPSS Score 0.00123
Published At June 4, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-06-02T04:39:57.114568+00:00 GitLab Importer Import https://gitlab.com/gitlab-org/advisories-community/-/blob/main/npm/@theia/mini-browser/CVE-2021-34435.yml 38.6.0