Description
The kramdown gem before 2.3.0 for Ruby processes the template option inside Kramdown documents by default, which allows unintended read access (such as template="/etc/passwd") or unintended embedded Ruby code execution (such as a string that begins with template="string://<%= `). NOTE: kramdown is used in Jekyll, GitLab Pages, GitHub Pages, and Thredded Forum.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | ruby-kramdown | 2.3.0-3 | — |
| Debian 13 | ruby-kramdown | 2.3.0-3 | — |
| Debian 12 | ruby-kramdown | 2.3.0-3 | — |
| Debian 10 | ruby-kramdown | 1.17.0-1+deb10u1 | DSA-4743-1 |
| Debian 9 | ruby-kramdown | 1.12.0-1+deb9u1 | DLA-2316-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | ruby-kramdown | 1.17.0-4ubuntu0.1 | USN-4562-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 18.04 LTS | ruby-kramdown | 1.15.0-1ubuntu0.1~esm1 | USN-9060-1 |
| Ubuntu Pro 16.04 LTS | ruby-kramdown | 1.10.0-1ubuntu0.1~esm1 | USN-9060-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP4 | rubygem-kramdown | 1.15.0-150000.3.3.1 | SUSE-SU-2022:3259-1 |
| SLES 15 SP3 | rubygem-kramdown | 1.15.0-150000.3.3.1 | SUSE-SU-2022:3259-1 |
| SLES 15 SP2 | rubygem-kramdown | 1.15.0-150000.3.3.1 | SUSE-SU-2022:3259-1 |
| SLES 15 SP1 | rubygem-kramdown | 1.15.0-150000.3.3.1 | SUSE-SU-2022:3259-1 |
| SLES 15 | rubygem-kramdown | 1.15.0-150000.3.3.1 | SUSE-SU-2022:3259-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | ruby3.2-rubygem-kramdown | 2.4.0-1.8 | openSUSE-SU-2024:13161-1 |
| openSUSE Tumbleweed | rubygem-kramdown | 2.4.0-1.1 | openSUSE-SU-2026:10352-1, openSUSE-SU-2025:15119-1, openSUSE-SU-2024:14170-1 |
| openSUSE Leap 15.4 | rubygem-kramdown | 1.15.0-150000.3.3.1 | SUSE-SU-2022:3259-1 |
| openSUSE Leap 15.3 | rubygem-kramdown | 1.15.0-150000.3.3.1 | SUSE-SU-2022:3259-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | icinga2 | 2.11.3-r1 | — |
| Alpine v3.23 | icinga2 | 2.11.3-r1 | — |
| Alpine v3.22 | icinga2 | 2.11.3-r1 | — |
| Alpine v3.21 | icinga2 | 2.11.3-r1 | — |
| Alpine v3.20 | icinga2 | 2.11.3-r1 | — |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | icinga2 | 2.11.3-r1 | — |
| Alpine v3.18 | icinga2 | 2.11.3-r1 | — |
| Alpine v3.17 | icinga2 | 2.11.3-r1 | — |
| Alpine v3.16 | icinga2 | 2.11.3-r1 | — |
| Alpine v3.15 | icinga2 | 2.11.3-r1 | — |
| Alpine v3.14 | icinga2 | 2.11.3-r1 | — |
| Alpine v3.13 | icinga2 | 2.11.3-r1 | — |
| Alpine v3.12 | icinga2 | 2.11.3-r1 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| RubyGems | kramdown | < 2.3.0 | 2.3.0 | GHSA-mqm2-cgpr-p4m6 |
Advisories 10
- USN-9060-1 ruby-kramdown vulnerability Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-4562-1 ruby-kramdown vulnerability Ubuntu Security Notices (USN) · Apr 27, 2026
- openSUSE-SU-2026:10352-1 ruby4.0-rubygem-kramdown-2.4.0-1.17 on GA media SUSE / openSUSE Security Updates · Mar 14, 2026
- DSA-4743-1 ruby-kramdown - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2316-1 ruby-kramdown - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:14170-1 ruby3.3-rubygem-kramdown-2.4.0-1.12 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:13161-1 ruby3.2-rubygem-kramdown-2.4.0-1.8 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2022:3259-1 Security update for rubygem-kramdown SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2025:15119-1 ruby3.4-rubygem-kramdown-2.4.0-1.15 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:12038-1 ruby3.1-rubygem-kramdown-2.4.0-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
References
- https://github.com/gettalong/kramdown
- https://kramdown.gettalong.org
- https://rubygems.org/gems/kramdown
- https://kramdown.gettalong.org/news.html
- https://github.com/gettalong/kramdown/commit/1b8fd33c3120bfc6e5164b449e2c2fc9c9306fde
- https://github.com/gettalong/kramdown/compare/REL_2_2_1...REL_2_3_0
- https://security.netapp.com/advisory/ntap-20200731-0004/
- [fluo-notifications] 20200808 [GitHub] [fluo-website] ctubbsii opened a new pull request #194: Update gems mailing-list
- [debian-lts-announce] 20200809 [SECURITY] [DLA 2316-1] ruby-kramdown security update mailing-list
- DSA-4743 vendor-advisory
- FEDORA-2020-f6eee9a2d3 vendor-advisory
- FEDORA-2020-5c70d97eca vendor-advisory
- USN-4562-1 vendor-advisory