{"answers":{"affected":"2 open source packages ship an affected version, including kramdown. It affects 3 products.","exploited":"There is no known exploitation of CVE-2021-28834 in the wild and no public exploit code.","fix":"Upgrade kramdown to 2.3.1 or later.","what":"CVE-2021-28834 is a critical code injection vulnerability in Debian Debian Linux, published on 19 Mar 2021. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2021-28834 and fix it if it is affected.\n\nWhat it is: CVE-2021-28834 is a critical code injection vulnerability in Debian Debian Linux, published on 19 Mar 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2021-28834 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- kramdown (RubyGems): affected from 1.16.0; fixed in 2.3.1\n- kramdown (RubyGems): affected from 1.16.0; fixed in 2.3.1\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2021-28834/ (Markdown: https://insights.sbomify.com/CVE-2021-28834/index.md)","id":"CVE-2021-28834","markdown":"https://insights.sbomify.com/CVE-2021-28834/index.md","name":"CVE-2021-28834","record":{"aliases":["DEBIAN-CVE-2021-28834","DSA-4890-1","GHSA-52p9-v744-mwjj","OESA-2021-1159","UBUNTU-CVE-2021-28834","USN-6424-1"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["code_execution"],"network_reachable":"yes","non_default_config":false,"product_category":"Ruby Markdown library","requires_auth":"none","summary":"Attackers can execute arbitrary code by instantiating unauthorized classes via the Rouge formatter interface in the Kramdown library.","user_interaction":"not_required","vuln_class":"code_injection"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"mitre","cpe":[{"product":"debian_linux","vendor":"debian"},{"product":"fedora","vendor":"fedoraproject"},{"product":"kramdown","vendor":"kramdown_project"}],"cvss":{"score":9.8,"severity":"critical","source":"nvd","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[],"description":"Kramdown before 2.3.1 does not restrict Rouge formatters to the Rouge::Formatters namespace, and thus arbitrary classes can be instantiated.","ecosystems":["RubyGems"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"Remote code execution in Kramdown","id":"CVE-2021-28834","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"RubyGems","product":"debian:debian_linux","products":["debian:debian_linux","fedoraproject:fedora"],"type":"code_injection","year":"2021"},"n_packages":2,"n_references":7,"next":{"headline":"Memory corruption in n/a","id":"CVE-2021-28835"},"packages":[{"ecosystem":"RubyGems","fixed":["2.3.1"],"introduced":["1.16.0"],"last_affected":[],"package":"kramdown","purl":null,"source":"GHSA-52p9-v744-mwjj"},{"ecosystem":"RubyGems","fixed":["2.3.1"],"introduced":["1.16.0"],"last_affected":[],"package":"kramdown","purl":"pkg:gem/kramdown","source":"GHSA-52p9-v744-mwjj"}],"prev":{"headline":"qiita-markdown Cross-site Scripting vulnerability","id":"CVE-2021-28833"},"products":["n/a"],"published":"2021-03-19","related":[{"cvss_score":10,"headline":"ProFTPD Improper Access Control","id":"CVE-2015-3306","kev_date_added":"2026-10-08","published":"2015-05-18"},{"cvss_score":9.9,"headline":"RoundCube Webmail Deserialization of Untrusted Data","id":"CVE-2025-49113","kev_date_added":"2026-02-20","published":"2025-06-02"},{"cvss_score":9.8,"headline":"GNU InetUtils Argument Injection","id":"CVE-2026-24061","kev_date_added":"2026-01-26","published":"2026-01-21"},{"cvss_score":9.8,"headline":"Linux Kernel Improper Check for Unusual or Exceptional Conditions","id":"CVE-2025-39682","kev_date_added":"2026-09-18","published":"2025-09-05"},{"cvss_score":9.8,"headline":"Mozilla Firefox Use-After-Free","id":"CVE-2024-9680","kev_date_added":"2024-10-15","published":"2024-10-09"},{"cvss_score":9.8,"headline":"RARLAB UnRAR Directory Traversal","id":"CVE-2022-30333","kev_date_added":"2022-08-09","published":"2022-05-09"},{"cvss_score":9.8,"headline":"Roundcube Webmail SQL Injection","id":"CVE-2021-44026","kev_date_added":"2023-06-22","published":"2021-11-19"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2024-08-03","vendors":["n/a"]},"summary":"Attackers can execute arbitrary code by instantiating unauthorized classes via the Rouge formatter interface in the Kramdown library.","url":"https://insights.sbomify.com/CVE-2021-28834/"}