Predictive Vulnerability Intelligence.

Product

  • Product
  • Pricing
  • Documentation

Company

  • About
  • Partnerships
  • Blog
  • Support

Legal

  • Terms
  • Privacy
  • Data Licensing

© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2021-29272

21
FAUCET Score

CVE-2021-29272 is a Cross-Site Scripting (XSS) vulnerability affecting microco bluemonday versions prior to 1.0.5. The flaw arises because Go's lowercasing function incorrectly processes an uppercase Cyrillic character, bypassing a defense designed to block the "script" string. This vulnerability has a CVSS score of 6.1 (Medium), indicating it can be exploited remotely with low attack complexity, requiring user interaction, and potentially leading to low impact on confidentiality and integrity. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
< 1.0.5CPE matchmatch criteria
cpe:2.3:a:microco:bluemonday:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

6.1MEDIUM

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
NONE
Exploitability Score
2.8
Impact Score
2.7
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.93%
Probability of exploitation in next 30 days
EPSS Percentile
56.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0093 is in the 69th percentile among its peer group of 26,221 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 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 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

gopatch availablevia ghsa
Product: github.com/microcosm-cc/bluemondayFixed in: 1.0.5

Vendor Advisories (2)

goGHSA-3x58-xr87-2fcjmedium

Cross-site scripting in bluemonday

May 18, 2021
redhatCVE-2021-29272Moderate

bluemonday: Cross-site scripting via uppercase Cyrillic i

Mar 27, 2021

References

github.com / microcosm-cc/bluemonday/releases/tag/v1.0.5
Third Party Advisory
vuln.ryotak.me / advisories/4
Third Party Advisory