Description
Kramdown before 2.3.1 does not restrict Rouge formatters to the Rouge::Formatters namespace, and thus arbitrary classes can be instantiated.
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 | 2.3.0-5 | — |
| Debian 13 | ruby-kramdown | 2.3.0-5 | — |
| Debian 12 | ruby-kramdown | 2.3.0-5 | — |
| Debian 10 | ruby-kramdown | 1.17.0-1+deb10u2 | DSA-4890-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | ruby-kramdown | 1.17.0-4ubuntu0.2 | USN-6424-1 |
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 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| RubyGems | kramdown | >= 1.16.0, < 2.3.1 | 2.3.1 | GHSA-52p9-v744-mwjj |
Advisories 7
- 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-4890-1 ruby-kramdown - security update Debian Security (DSA / DLA) · Mar 9, 2026
- USN-6424-1 ruby-kramdown vulnerability Ubuntu Security Notices (USN) · Feb 10, 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
- 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/pull/708
- https://gitlab.com/gitlab-org/gitlab/-/commit/179329b5c3c118924fb242dc449d06b4ed6ccb66
- https://github.com/gettalong/kramdown/compare/REL_2_3_0...REL_2_3_1
- FEDORA-2021-139a6a2f9d vendor-advisory
- FEDORA-2021-4c57a892d1 vendor-advisory
- FEDORA-2021-edc673e864 vendor-advisory
- DSA-4890 vendor-advisory