CVE-2021-43842 | Stored XSS via SVG file upload in Wiki.js

Wiki.js is a wiki app built on Node.js. Wiki.js versions 2.5.257 and earlier are vulnerable to stored cross-site scripting through a SVG file upload. By creating a crafted SVG file, a malicious Wiki.js user may stage a stored cross-site scripting attack. This allows the attacker to execute malicious JavaScript when the SVG is viewed directly by other users. Scripts do not execute when loaded inside a page via normal `<img>` tags. Commit 5d3e81496fba1f0fbd64eeb855f30f69a9040718 fixes this vulnerability by adding an optional (enabled by default) SVG sanitization step to all file uploads that match the SVG mime type. As a workaround, disable file upload for all non-trusted users. Wiki.js version 2.5.260 is the first production version to contain a patch. Version 2.5.258 is the first development build to contain a patch and is available only as a Docker image as requarks/wiki:canary-2.5.258.

Published: 2021-12-20 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-43842 is rated Low Risk (39.2/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.72%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-43842

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.25% 0.72% +0.47%
2 2025-03-30 0.22% 0.25% +0.03%
3 2025-03-29 — 0.22% —

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-43842

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.4 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.3 2.7 [email protected]
3.5 2.0 LOW
AV:N/AC:M/Au:S/C:N/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 6.8 2.9 [email protected]

Weakness enumeration for CVE-2021-43842

Affected software / configurations for CVE-2021-43842

Vendor Product Version Raw CPE
requarks wiki.js <= 2.5.257 cpe:2.3:a:requarks:wiki.js:*:*:*:*:*:*:*:*

References for CVE-2021-43842

cvelogic Threat Intelligence