{"id":"UBUNTU-CVE-2026-54911","details":"UltraJSON is a fast JSON encoder and decoder written in pure C with bindings for Python 3.7+. Prior to 5.13.0, ujson.dumps() (or ujson.dump() or ujson.encode()) have a reject_bytes=False option. When set, they may accept malformed or truncated UTF-8 byte sequences, silently rewriting them into different Unicode characters instead of rejecting them. This leads to input validation bypass and data integrity issues. This vulnerability is fixed in 5.13.0.","modified":"2026-06-24T09:03:12Z","published":"2026-06-22T22:16:00Z","upstream":["CVE-2026-54911"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-54911"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-54911"},{"type":"REPORT","url":"https://github.com/ultrajson/ultrajson/commit/169eaf36b1116fece5034ee79a7a0ef3f6deedcf"},{"type":"REPORT","url":"https://github.com/ultrajson/ultrajson/releases/tag/5.13.0"},{"type":"REPORT","url":"https://github.com/ultrajson/ultrajson/security/advisories/GHSA-3j69-69wj-xqx2"}],"affected":[{"package":{"name":"pandas","ecosystem":"Ubuntu:14.04:LTS","purl":"pkg:deb/ubuntu/pandas?arch=source&distro=trusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.12.0-2ubuntu1","0.13.1-2ubuntu1","0.13.1-2ubuntu2"],"ecosystem_specific":{"binaries":[{"binary_name":"python-pandas","binary_version":"0.13.1-2ubuntu2"},{"binary_name":"python-pandas-lib","binary_version":"0.13.1-2ubuntu2"},{"binary_version":"0.13.1-2ubuntu2","binary_name":"python3-pandas"},{"binary_version":"0.13.1-2ubuntu2","binary_name":"python3-pandas-lib"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-54911.json"}},{"package":{"name":"collada2gltf","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/collada2gltf?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["20140924-3"],"ecosystem_specific":{"binaries":[{"binary_name":"libcollada2gltfconvert-dev","binary_version":"20140924-3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-54911.json"}},{"package":{"name":"pandas","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/pandas?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.15.0-2","0.15.0-2ubuntu1","0.15.0-2ubuntu2","0.17.1-3ubuntu2"],"ecosystem_specific":{"binaries":[{"binary_name":"python-pandas","binary_version":"0.17.1-3ubuntu2"},{"binary_name":"python-pandas-lib","binary_version":"0.17.1-3ubuntu2"},{"binary_name":"python3-pandas","binary_version":"0.17.1-3ubuntu2"},{"binary_version":"0.17.1-3ubuntu2","binary_name":"python3-pandas-lib"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-54911.json"}},{"package":{"name":"ujson","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/ujson?arch=source&distro=esm-apps%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.33-1","1.33-1build1","1.33-1ubuntu0.1~esm2"],"ecosystem_specific":{"binaries":[{"binary_name":"python-ujson","binary_version":"1.33-1ubuntu0.1~esm2"},{"binary_version":"1.33-1ubuntu0.1~esm2","binary_name":"python3-ujson"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-54911.json"}},{"package":{"name":"collada2gltf","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/collada2gltf?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["20140924-4"],"ecosystem_specific":{"binaries":[{"binary_version":"20140924-4","binary_name":"libcollada2gltfconvert-dev"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-54911.json"}},{"package":{"name":"pandas","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/pandas?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.19.2-5.1ubuntu4","0.22.0-2ubuntu1","0.22.0-3","0.22.0-4","0.22.0-4ubuntu1"],"ecosystem_specific":{"binaries":[{"binary_name":"python-pandas","binary_version":"0.22.0-4ubuntu1"},{"binary_name":"python-pandas-lib","binary_version":"0.22.0-4ubuntu1"},{"binary_version":"0.22.0-4ubuntu1","binary_name":"python3-pandas"},{"binary_name":"python3-pandas-lib","binary_version":"0.22.0-4ubuntu1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-54911.json"}},{"package":{"name":"ujson","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/ujson?arch=source&distro=esm-apps%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.35-1build2","1.35-2","1.35-2ubuntu0.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.35-2ubuntu0.1~esm1","binary_name":"python-ujson"},{"binary_name":"python3-ujson","binary_version":"1.35-2ubuntu0.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-54911.json"}},{"package":{"name":"pandas","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/pandas?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.23.3+dfsg-4ubuntu1","0.23.3+dfsg-4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