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CVE-2021-43855

20
FAUCET Score

CVE-2021-43855 is a stored cross-site scripting (XSS) vulnerability affecting Wiki.js versions 2.5.263 and earlier. An authenticated attacker can upload a specially crafted SVG file with a fake MIME type, leading to the execution of malicious JavaScript when other users view the SVG directly. This vulnerability has a CVSS score of 5.4 (Medium), indicating a network-based attack with low privileges, requiring user interaction, and resulting in low confidentiality and integrity impacts. There is no evidence of active exploitation, public exploit code, or significant community discussion, and it is not listed in CISA's KEV catalog. A patch in version 2.5.264 addresses this by enhancing SVG file extension verification.

Impacted Technologies

VendorProductVersion(s)CPE
< 2.5.264CPE matchmatch criteria
cpe:2.3:a:requarks:wiki.js:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

8.2HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
LOW
Availability Impact
NONE
Exploitability Score
2.8
Impact Score
4.7
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.89%
Probability of exploitation in next 30 days
EPSS Percentile
55.6%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0089 is in the 90th percentile among its peer group of 15,225 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

github_advisorypatch availablevia nvd_reference
View patch

References

github.com / Requarks/wiki/commit/57b56d3a5b9c00358814e76f3ee5b4bb353ad62f
PatchThird Party Advisory
github.com / Requarks/wiki/releases/tag/2.5.264
Release NotesThird Party Advisory
github.com / Requarks/wiki/security/advisories/GHSA-4893-pj5w-3hq9
ExploitPatchThird Party Advisory