CVE-2021-29272
Cross-site scripting in bluemonday
bluemonday before 1.0.5 allows XSS because certain Go lowercasing converts an uppercase Cyrillic character, defeating a protection mechanism against the "script" string.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
bluemonday before 1.0.5 allows XSS because certain Go lowercasing converts an uppercase Cyrillic character, defeating a protection mechanism against the "script" string.
- Record
CVE-2021-29272- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:N/I:P/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
CVE List No score
bluemonday before 1.0.5 allows XSS because certain Go lowercasing converts an uppercase Cyrillic character, defeating a protection mechanism against the "script" string.
- Record
CVE-2021-29272- Updated
- 2026-11-02
EUVDEUVD-2021-0925 No score
bluemonday before 1.0.5 allows XSS because certain Go lowercasing converts an uppercase Cyrillic character, defeating a protection mechanism against the "script" string.
- Record
EUVD-2021-0925- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-3x58-xr87-2fcj
Cross-site scripting in bluemonday
bluemonday before 1.0.5 allows XSS because certain Go lowercasing converts an uppercase Cyrillic character, defeating a protection mechanism against the "script" string.
- Record
GHSA-3x58-xr87-2fcj- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSVALPINE-CVE-2021-29272
bluemonday before 1.0.5 allows XSS because certain Go lowercasing converts an uppercase Cyrillic character, defeating a protection mechanism against the "script" string.
- Record
ALPINE-CVE-2021-29272- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-03
OSV
bluemonday before 1.0.5 allows XSS because certain Go lowercasing converts an uppercase Cyrillic character, defeating a protection mechanism against the "script" string.
- Record
CVE-2021-29272- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
OSVGHSA-3x58-xr87-2fcj
Cross-site scripting in bluemonday
bluemonday before 1.0.5 allows XSS because certain Go lowercasing converts an uppercase Cyrillic character, defeating a protection mechanism against the "script" string.
- Record
GHSA-3x58-xr87-2fcj- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSVUBUNTU-CVE-2021-29272
bluemonday before 1.0.5 allows XSS because certain Go lowercasing converts an uppercase Cyrillic character, defeating a protection mechanism against the "script" string.
- Record
UBUNTU-CVE-2021-29272- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
OSVGO-2022-0762 No score
Cross-site scripting due to incorrect sanitization in github.com/microcosm-cc/bluemonday
An XSS injection was possible because the sanitization of the Cyrillic character i bypass a protection mechanism against user-inputted HTML elements such as the <script> tag.
- Record
GO-2022-0762- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
github.com/microcosm-cc/bluemondayGo |
before 1.0.5 | 1.0.5 |
giteaAlpine:v3.12 |
before 1.13.7 | 1.13.7 |
giteaAlpine:v3.13 |
before 1.13.7-r0 | 1.13.7-r0 |
giteaAlpine:v3.14 |
before 1.13.7-r0 | 1.13.7-r0 |
giteaAlpine:v3.15 |
before 1.13.7-r0 | 1.13.7-r0 |
giteaAlpine:v3.16 |
before 1.13.7-r0 | 1.13.7-r0 |
giteaAlpine:v3.17 |
before 1.13.7-r0 | 1.13.7-r0 |
giteaAlpine:v3.18 |
before 1.13.7-r0 | 1.13.7-r0 |
giteaAlpine:v3.19 |
before 1.13.7-r0 | 1.13.7-r0 |
giteaAlpine:v3.20 |
before 1.13.7-r0 | 1.13.7-r0 |
Show 6 moreShow less
| Package | Affected | Fixed |
|---|---|---|
giteaAlpine:v3.21 |
before 1.13.7-r0 | 1.13.7-r0 |
giteaAlpine:v3.22 |
before 1.13.7-r0 | 1.13.7-r0 |
giteaAlpine:v3.23 |
before 1.13.7-r0 | 1.13.7-r0 |
giteaAlpine:v3.24 |
before 1.13.7-r0 | 1.13.7-r0 |
golang-github-microcosm-cc-bluemondayUbuntu:18.04:LTS |
All versions, plus listed versions 0.0~git20161202.0.e797637-10.0~git20161202.0.e797637-1.1 |
None known |
golang-github-microcosm-cc-bluemondayUbuntu:22.04:LTS |
All versions, plus listed versions 1.0.2-41.0.6-11.0.16-1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, aliases, references | OSV | |
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-29272 is a medium vulnerability (CVSS 6.1) in Microco Bluemonday, published March 27, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.93%, the 60th percentile. Fixed in github.com/microcosm-cc/bluemonday 1.0.5.